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26 data found. 1 - 26 listed

Published online: 14th November, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14171
Piperidine and Azetidine Formation by Direct Cyclization of Diols with N-Nonsubstituted Sulfonamide under The Mitsunobu Conditions Utilizing (Cyanomethylene)Tributylphosphorane (Cmbp) and Its Application to The Synthesis of Lupinine

Hiroto Kaku,* Yuhei Sonoda, Hideyuki Hishida, Yuri Taniguchi, Akiko Kubo, Takumi Hamaguchi, Mitsuyo Horikawa, Makoto Inai, Kei Kitamura, and Tetsuto Tsunoda*

*Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihamabouji, Yamashiro-machi, Tokushima, 770-8514, Japan

Abstract

(Cyanomethylene)tributylphosphorane (CMBP) can promote the Mitsunobu reaction of 1,3- and 1,5-diols with N-nonsubstituted sulfonamides, such as tosylamide (TsNH2) and 3,3-dimethoxypropylsulfonamide (DimpsNH2), to prepare azetidine and piperidine ring systems directly. Utilizing this methodology, lupinine, a biologically active piperidine alkaloid, was synthesized.

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Published online: 13th November, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14164
Isochromophilol A, A New Azaphilone Isolated from Penicillium Sp. RO369, A Leaf Litter Inhabiting Fungus from Tsuga Diversifolia

Kan'ichiro Ishiuchi,* Dai Hirose, Yoriko Takahashi, Ryu Miyagawa, Kohei Watanabe, and Susumu Kitanaka*

*Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1, Tanabe-Dori, Mizuho-ku, Nagoya, Aichi, 467-8603, Japan

Abstract

A new sclerotiorin-type azaphilone, isochromophilol A (1), was isolated from Penicillium sp. RO369 associated with Tsuga diversifolia, along with eight known compounds (29). The structure of 1 was elucidated on the basis of spectroscopic data. Isochromophilol A (1) (16 μg) showed weak anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity with an inhibition diameter of 8.8 ± 1.0 mm

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Published online: 8th November, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14160
A Propeller-Shaped Mesomeric Betaine, Tetraphenylbenzene-1-Quinolinium-2-Benzoate

Sviatoslav Batsyts, Felix Lederle, Eike G. Hübner, Jörg Adams, Jan C. Namyslo, and Andreas Schmidt*

*Institute of Organic Chemistry, Clausthal University of Technology, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, Germany

Abstract

4-[(Quinolin-4-yl)ethynyl]benzoic acid underwent a cycloreaction with tetraphenylcyclopentadienone to give the hexa(hetero)arylbenzene- 1-(quinolin-4-yl)-2-(4-benzoic acid)-3,4,5,6-tetraphenylbenzene which was N-methylated and finally deprotonated to give the title compound. The molecule adopts a propeller-shaped configuration in which the benzoate ring as well as the phenyl ring adjacent to the quinolinium substituent display non-isochronous resonance frequencies, respectively, due to a hindered rotation. Although the molecule formally belongs to the class of pseudo-cross-conjugated heterocyclic mesomeric betaines, the propeller-shape causes a charge distribution of cross-conjugated systems. DFT-calculations (frontier orbital profiles, geometries) have been carried out.

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Published online: 7th November, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14162
One-pot synthesis of pyrrolo[2,1-α]isoquinolines via tandem reactions of vinylselenonium salt, 2-bromoethanones, and isoquinoline

Qi Sun, Minghong Liao, Yan Zhao, Yunxia Li, Shanshan Liu, Deshou Mao,* and E Tang*

*School of Chemical Science and Technology, Yunnan University, No. 2 Green Lake North Road, Kunming 650091, China

Abstract

An convenient and one-pot synthesis of pyrrolo[2,1-a]isoquinolines via the tandem reaction of methyl(phenyl)vinylselenonium salt with isoquinoline and 2-bromoethanones has been developed, which features very mild conditions, available substrates, simple experimental procedures, moderate to good yields, and wide functional group tolerance.

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Published online: 6th November, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14167
A Highly Selective Fluorescence-Enhanced Probe for The Rapid Detection of So2 Derivatives and Its Bio-Imaging in Living Cells

Yaogen Zhou, Yiwei Zhou, Hongying Wang,* and Baoquan Chen*

*School of Chemistry and Chemical Engineering, Tianjin University of Technology, 391 Binshui Xidao, Xiqing District Tianjin 300384, China

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Published online: 5th November, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14157
Rearrangement Reaction in 1-Hydroxyindole Chemistry: A Synthesis of Novel 7-Substituted Yohimbine, and 4a-Substituted 1,2,3,4-Tetrahydro-β-Carboline DerivaTives1

Katsumasa Yoshino, Fumio Yamada, Koichi Noguchi, Kiyoka Kusuno, and Masanori Somei*

*Noto Marine Laboratory, Institute of Nature and Environmental Technology, Faculty of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, 56-7 Matsuhidai, Matsudo-shi, Chiba 270-2214, Japan

Abstract

X-Ray analyses of 1-hydroxyyohimbine derivatives definitely show the deviation of the N(1)—O bond from the indole molecular plane. This fact supports our working hypothesis “bishomoallylic conjugation”. The deviation is responsible for the rearrangement reaction in 1-hydroxyindole chemistry. Effective synthetic method for novel 7α- and 7β-heteroarylyohimbine, and 4aα- and 4aβ-heteroaryl-1,2,3,4-tetrahydro-β-carboline derivatives are reported.

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Published online: 1st November, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14158
Fast, Solvent-Free, and Highly Efficient Synthesis of Pyrazolo[3,4-b]Pyridines Using Microwave Irradiation and Khso4 as A Reusable Green Catalyst

Jinjing Qin, Zhenhua Li,* Xiaomeng Sun, Yi Jin, and Weike Su

*Collaborative Innovation Centre of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, 18#, Chaowang Rd., Hangzhou, Zhejiang 310014, China

Abstract

A simple, ecofriendly, and effective method was described for forming pyrazolo[3,4-b]pyridines from 5-aminopyrazoles and 3-formylchromones, in good to excellent yields, under microwave irradiation in solvent-free conditions using KHSO4 as a reusable catalyst. Some noteworthy features of this method were its cleanliness, short reaction time, easy work-up, and broad substrate tolerance. The catalyst was reused several times without losing activity.

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Published online: 1st November, 2019

Review | Regular issue | Prepress
DOI: 10.3987/REV-19-916
Asymmetric Construction of Heterocycles via Dearomative Coupling and Addition Reactions of Phenol and Aniline Derivatives

Kotaro Kikushima,* Hideyasu China, and Toshifumi Dohi*

*College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga, 525-8577, Japan

Abstract

Efficient methods for the formation of chiral heterocycles are considerably important in the synthesis of naturally-occurring compounds and pharmaceutical products. This review highlights the formation of chiral heterocycles through dearomative bond-formations as the key reactions, wherein the phenol or aniline derivatives serve as the nucleophiles. Transition-metal-catalyzed intramolecular coupling reactions in the presence of chiral ligands afford the enantioenriched multicyclic compounds bearing heterocycles. Chiral bifunctional organocatalysts induce the formation of dearomative coupling products, which could be converted to heterocycles through further transformations.

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Published online: 30th October, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14166
Facile Synthesis of (Guaiazulene-1-Yl)-1h-Pyrroles via Paal-Knorr Reaction

Lu Zhang, Dao-Lin Wang,* Jin-Juan Xing, and Lin Liu

*College of Chemistry and Chemical Engineering, Bohai University, 19, Keji Rd., New Songshan District, Jinzhou City, Liaoning Province 121001, China

Abstract

An efficient and simple method for the synthesis of (guaiazulen-1-yl)-1H-pyrroles was described. The construction of this new heteroarylazulene system was achieved by a the Paal-Knorr reaction of 3-acetyl-4-(guaiazulen-1-yl)hexane- 2,5-dione (4), easily preparation by a three-component condensation of guaiazulene (1), methylglyoxal (2) and acetylacetone (3), with primary amines (5).

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Published online: 29th October, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14132
Unexpected Formation of 4,7-Dihalobenzo[B]Thiophenes Using Ohira-Bestmann Reagent and Reactivity of The Halogen-Substituted Benzo[B]Thiophenes in Suzuki-Miyaura Coupling with Phenylboronic Acid

Kozo Toyota,* Hirotaka Mutoh, Hiroki Kishi, Shinichi Mikami, Hiroki Tanaka, Shuhei Yoshida, and Daisuke Naganuma

*Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan

Abstract

Reaction of 2-(1-adamantylsulfanyl)-3,6-dihalobenzaldehydes with Ohira-Bestmann reagent gave 4,7-dihalobenzo[b]thiophenes along with normal alkyne products. Nine types of 4,7-dihalobenzo[b]thiophenes bearing chlorine, bromine, or iodine atoms, were prepared by this method. Regioselectivity in Suzuki-Miyaura cross coupling reactions of the 4,7-dihalobenzo[b]thiophenes with PhB(OH)2 was also studied.

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Published online: 29th October, 2019

Review | Regular issue | Prepress
DOI: 10.3987/REV-19-914
Recent Advances in Transition-Metal-Catalyzed Synthesis of 3- and/or 4-Aryl-2(1H)-Quinolones

Yoshihiko Yamamoto*

*Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan

Abstract

2(1H)-Quinolone is a privileged nitrogen heterocycle that is found in various bioactive compounds and functional molecules. In particular, derivatives possessing aryl substituents at the 3- and/or 4-positions are significant synthetic targets as they are promising drug leads. This review surveys the synthetic methods for 3- and/or 4-aryl-2(1H)-quinolones that involve transition-metal-catalyzed construction of the 2(1H)-quinolone framework. Transition-metal-catalyzed arylations of 2(1H)-quinolone scaffolds are also surveyed.

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Published online: 28th October, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14161
Elucidation of The Conformational Properties of 3-Pyridinoyl Indoles as Intermediates of Cannabimimetics

Hideyo Takahashi,* Koji Araki, Hidetsugu Tabata, Kosho Makino, Ryohei Ujiie, Kohei Sezaki, Hiroshi Nakayama, Tetsuta Oshitari, and Hideaki Natsugari

*Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan

Abstract

The conformations of 3-pyridinoyl indoles, which are intermediates of 5-fluoropentyl-3-pyridinoyl indole, were investigated using their X-ray crystal structures. All derivatives existed as s-trans conformers. A pseudo-planar conformation was observed in the 2'-yl isomer of 3-pyridinoyl indoles. On the other hand, twisted conformations were observed in 3-pyridinoyl 2-methylindoles. The conformations of these compounds in solution were also investigated using VT-NMR.

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Published online: 25th October, 2019

Communication | Regular issue | Prepress
DOI: 10.3987/COM-19-14163
Interaction of the Dihydropyridine/Pyridinium Redox Pair Fixed into a V-Shaped Conformation

Yasukazu Hirao,* Mitsuru Teraoka, and Takashi Kubo*

*Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan

Abstract

A new V-shaped molecule incorporating a dihydropyridine and a pyridinium moiety was synthesized and evaluated for its effect on the interaction between the hydride donor-acceptor pair. Spectroscopic, electrochemical, and computational studies have revealed the presence of the charge transfer interaction as a consequence of the electron donor-acceptor association.

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Published online: 17th October, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14142
Anti-Tmv Isoquinoline Alkaloids from The Whole Plants of Thalictrum glandulosissimum

Chun-Man Song,* Guang-Hui Kong, Yu-Ping Wu, Eric Yin, Bradley Liu, Zhen-Yuan Xia, Hai-Tao Huang, Guang-Yu Yang, and Qiu-Fen Hu*

*Chemistry, Cyats, Keyi Rd 653100, China

Abstract

Three new (1-3), together with three known (4-6) isoquinoline alkaloids were isolated from the whole plants of Thalictrum glandulosissimum. Their structures were elucidated by spectroscopic methods, including extensive 1H, 13C, and 2D-NMR techniques. Compounds 1-6 were evaluated for their anti-tobacco mosaic virus (Anti-TMV) activity. The results revealed that compounds 2, 3 and 4 showed potential anti-TMV activities with inhibition rates of (35.6±3.5)%, (36.2%±3.8)%, (46.3%±3.2)%, at the concentration of 20 µM, respectively. These rates are higher than that of positive control.

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Published online: 16th October, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14147
Synthesis of Cycloalkyl/Steroidal Heteroaryl Sulfides Using Rhodium-Catalyzed Heteroaryl Exchange Reaction

Mieko Arisawa,* Katsuya Nakai, Tomoki Yamada, Ren Suzuki, and Masahiko Yamaguchi*

*Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba-ku, sendai 980-8578, Japan

Abstract

Cycloalkyl heteroaryl sulfides are efficiently synthesized by the single-bond cleavage and exchange reaction of S-cycloalkyl thioesters and heteroaryl ethers without using a base. The method is applicable to steroids at the A- and D-rings, and provides diverse heteroarylthiolated steroids with five- and six-membered heteroarenes.

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Published online: 8th October, 2019

Communication | Regular issue | Prepress
DOI: 10.3987/COM-19-14117
Synthetic Studies on Keramaphidin B: Formation of a Macrocyclic Ring by Intramolecular Diels-Alder Reaction

Hiroki Shimoda, Takahiro Shibata, Daisuke Sekine, and Masahisa Nakada*

*Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan

Abstract

The possibility of constructing the macrocyclic ring of keramaphidin B via an intramolecular Diels-Alder (IMDA) reaction has been investigated. The IMDA reaction of a substrate possessing dihydropyridone and diene moieties, which were tethered by an alkyl chain including a linear triple bond, was found to proceed in the presence of SnCl4 at 80 °C.

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Published online: 8th October, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14139
Benzylic Oxidation and Functionalizations of Xanthenes by Ligand Trasfer Reactions of Hypervalent Iodine Reagents

Toshifumi Dohi, Keina Komiyama, Shohei Ueda, Nobutaka Yamaoka, Motoki Ito, and Yasuyuki Kita*

*Research Organization of Science and Technology, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga, 525-8577, Japan

Abstract

The benzylic oxidation, amidation, and unprecedented heteroarylation proceed at room temperature using iodosobenzene, (sulfonylimido)iodobenzenes, and diaryliodonium(III) salts are described for the direct Csp3-H functionalizations of xanthene molecules. This study has demonstrated that hypervalent iodine reagents serve as unified synthetic tools for versatile xanthene Csp3-H transformations based on the radical and SET oxidation processes.

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Published online: 4th October, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14151
The One-Pot Synthesis of Pyridine Derivatives from The Corresponding 1,5-Dicarbonyl Compounds

Hiromichi Mihara, Takeru Miyakoshi, Yui Kikuchi, and Hiroyuki Konno*

*Graduate School of Science and Engineering, Yamagata University, 3-16 Jonan 4-Chome, Yonezawa 992-8510, Japan

Abstract

The optimization of the one-pot, acid-promoted synthesis of pyridine and alkylpyridine derivatives from simple alkyl-1,5-dicarbonyl derivatives and via the corresponding oxime intermediate is described. Of all the combinations of acids and solvents tested, the use of HCl in refluxing dioxane was found to result in the highest chemical yields. Twelve pyridines were prepared using this method.

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Published online: 24th September, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14123
Synthetic Studies on Marineosins Based on a Direct Coupling Reaction of Pyrrole and δ-Lactone

Kohei Yamamoto, Yuki Morii, Akihisa Suga, Keita Komine, Hayato Fukuda, Jun Ishihara,* and Susumi Hatakeyama*

*Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan

Abstract

A promising precursor of marineosins A and B, unusual macrocyclic pyrrole and spiroiminal alkaloids isolated from marine microorganism has been synthesized employing a direct coupling of pyrrole and δ-lactone.

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Published online: 24th September, 2019

Communication | Regular issue | Prepress
DOI: 10.3987/COM-19-14124
Alternative Chiral Preparations of a Swaminathan Ketone via Asymmetric Aldol Reactions Mediated by Chiral Amines Bearing a Pyrrolidine

Yuichi Akahane, Arisa Miura, and Kohei Inomata*

*Phamaceutical Department, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan

Abstract

We established a novel chiral route to provide a Swaminathan ketone (3) bearing a 7-membered ring via intramolecular aldol reaction of trione (7) mediated by chiral pyrrodinylmethylamine derivatives. Despite the moderate enantioselectivity of 3, we succeeded in increasing optical purities by using a lipase-mediated asymmetric esterification of an alcohol (16) at a later synthetic stage. The absolute configuration was determined by Mosher’s ester method, and relations between absolute configurations and optical rotations of 3 were clarified.

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Published online: 20th September, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14118
Syntheses of Indirubins by Aldol Condensation of Isatins with Indoxyl Anion Generated in situ by Lipase-Catalyzed Deacetylation of Indoxyl Acetate

Takeshi Sugai,* Kengo Hanaya, and Shuhei Higashibayashi

*Department of Pharmaceutical Sciences, Faculty of Pharmacy, Keio University, 1-5-30 Shiba-Kouen, Minato-ku, Tokyo, Japan

Abstract

The syntheses of indirubin (76% yield), 6-bromoindirubin (82% yield), and 6-bromoindirubin-3′-oxime (78% yield in two steps) were achieved via the lipase-triggered aldol condensation between isatins and an indoxyl anion in tetrahydrofuran under anhydrous and anaerobic conditions as the key step. The aldol donor was generated in situ by Burkholderia cepacia lipase (Amano PS-IM)-catalyzed deacetylation of commercially available and stable indoxyl acetate in the presence of triethylamine and with 2-propanol as the transesterification reagent. The scale-up of the presently developed reactions is easier than that in the previously reported chemical aldol condensations, because of the simplicity of the isolation procedure and suppression of the oxidative byproduct formation from indoxyl acetate.

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Published online: 20th September, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14130
Artificial Intelligence-Designed Stereoselective One-Pot Synthesis of trans-β-Lactams and Its Application to Cholesterol Absorption Inhibitor SCH 47949 Synthesis

Tetsuhiko Takabatake, Takumi Yoneda, Jyo Otsuka, Natsuko Kagawa, and Masahiro Toyota*

*Department of Chemistry, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan

Abstract

Cholesterol absorption inhibitor drug SCH 47949 is synthesized stereoselectively using an artificial intelligence design proposed by SYNSUP. The key step involves a stereoselective one-pot preparation of the trans-β-lactam system through thermal electrocyclization. The trans-β-lactam intermediate is converted to SCH 47949 by a series of functional group transformations proposed by SYNSUP.

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Published online: 30th August, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14120
An Improved Synthesis of a Salicylated Divinylcarbinol Derivative as a Part of Salicylic Macrolides

Aki Kohyama, Yoshihito Oguma, Takumi Yamagishi, Kenji Sugimoto, and Yuji Matsuya*

*Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan

Abstract

An improved enantioselective synthesis of (R)-salicylated divinyl carbinol derivative (4), the key intermediate for the total synthesis of natural salicyclic macrolides, has been achieved. Key steps of the synthesis involve the introduction of the chirality by reliable Sharpless asymmetric epoxidation, carbon-carbon bond formation via Heck reaction and the regeneration of a terminal alkene structure via deoxygenation. The efficient route shortened the reaction sequence and enabled the preparation of (R)-4 in 4 steps in 28% overall yield from divinyl carbinol.

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Published online: 21st August, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14096
Synthesis of 4-Aroyl-5-arylpyrazoles and 4-Aroyl-3-arylpyrazoles via the Reaction of Enaminodiketones with Substituted Hydrazines

Rika Kotouge, Takashi Nishiyama, Akira Yamauchi, Kanako Ono, Noriyuki Hatae, Tsutomu Oikawa, Satoshi Hibino, and Tominari Choshi*

*Graduate School of Pharmacy & Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan

Abstract

Pyrazole is a five-membered heterocyclic compound and is one of the important heterocycles in the fields of medicine and pharmacology. Here, we demonstrate the reactivity of symmetrical enaminodiketones 814 with substituted hydrazines. When using alkylhydrazines, if the substituent size of the alkyl group is small, it is possible to selectively synthesize 1-substituted 4-aroyl-5-arylpyrazoles and their regioisomers, 1-substituted 4-aroyl-3-arylpyrazoles, by choosing the solvent (EtOH or toluene). When they react with bulky substituted hydrazines (e.g., cyclohexyl, phenyl, or pyridyl), only 1-substituted 4-aroyl-5-arylpyrazoles are selectively obtained.

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Published online: 20th August, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14122
Platinum on Carbon–Catalyzed and Chemoselective Aqueous Oxygen Oxidation of Aromatic Acetals to Benzoic Acids

Naoki Yasukawa, Takumi Matsuda, Eisho Shimizu, Hironao Sajiki,* and Yoshinari Sawama*

*Laboratory of Organic Chemistry, Department of Pharmaceutical Sciences, Gifu Pharmaceutical University, 1-25-4 Daigakunishi, Gifu 501-1196, Japan

Abstract

Novel chemoselective transformations can diversify the synthetic pathways of the target molecules. The chemoselective oxidation of aromatic acetals to benzoic acid derivatives under platinum on carbon (Pt/C)–catalyzed oxygen oxidation conditions has been newly developed with a tolerance of aliphatic acetals and ketals. The present oxidation was clean and useful from the viewpoint of the easy removal of Pt/C and the use of molecular oxygen as a green oxidant in water as an abundant, non-toxic and environmentally friendly solvent.

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Published online: 12th March, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-19-14033
Synthesis of 1,2-Benzothiazole-3(2H)-thione 1,1-Dioxides by DBU-Promoted Cyclization of 2-(Aminosulfonyl)-N-methylbenzothioamide Derivatives

Kazuhiro Kobayashi* and Daiki Fujiwara

*Applied Chemistry Field, Chemistry and Biotechnology Course, Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan

Abstract

An efficient method for the preparation of 2-alkyl-1,2-benzothiazole-3(2H)-thione 1,1-dioxides has been developed. Thus, the reaction of 2,N-dilithio derivatives of N-alkylbenzenesulfonamides with methyl isothiocyanate affords 2-[(alkylamino)sulfonyl]-N-methylbenzothioamides, which are treated with a catalytic amount of DBU in refluxing toluene to provide the desired products in moderate to good yields.

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26 data found. 1 - 26 listed