The simplest synthesis of 5,5-disubstituted and spiranic methyl 4-amino-2,2-dioxo-2,5-dihydro-1,2λ6-oxathiole-3-carboxylates

We report the short and the simplest strategy for the synthesis of methyl 4-amino-2,2-dioxo-2,5-dihydro-1,2λ⁶-oxathiole-3-carboxylates bearing aliphatic substituents at the 5th position. A number of cyanohydrins were forced to react with methyl 2-(chlorosulfonyl)acetate to give the interim methyl 2-[(cyanomethoxy)sulfonyl]acetates that upon Et₃N-mediated conditions underwent the CSIC [Carbanion mediated Sulfonate (Sulfonamido) Intramolecular Cyclization] reaction yielding the 5,5-disubstituted and spiranic methyl 4-amino-2,2-dioxo-2,5-dihydro-1,2λ⁶-oxathiole-3-carboxylates.     

Synthesis of structurally constrained 4-quinazolinone derivatives with a tetrahedral C-2 atom present in three rings

The reaction of 2-aminobenzamides with 2-oxocyclopentane-, 2-oxocyclohexane-, and 2-oxocycloheptaneacetic acids esters was found to give 7a,8,9,10-tetrahydrocyclopenta[2,3]pyrrolo[1,2-a]quinazoline-6,12(7H,11H)-diones, 7,7a,8,9,10,11-hexahydro-6H-indolo[1,7a-a]quinazoline-6,13(12H)-diones, and 7a,8,9,10,11,12-hexahydrocyclohepta[2,3]pyrrolo[1,2-a]quinazoline-6,14(7H,13H)-diones, respectively. The relative configuration with the cis-fused butyrolactam and cycloalkane rings was assigned to the prepared compounds on the basis of an X-ray crystallographic study.     

Synthesis of condensed tetrahydroimidazo[1,2-a]quinazoline-1,5-dione derivatives

Heating of N-{2-[(R-amino)carbonyl]phenyl}prolinamides in triethyl orthoformate solution was found to give 6-R-5,6,6a,8,9,10,10a,11-octahydropyrrolo[1′,2′:3,4]imidazo[1,2-a]quinazoline-5,11-diones. Similar reaction of N-{2-[(R-amino)carbonyl]phenyl}thiazolidine-4-carboxamides afforded 6-R-5,6,6a,10,10a,11-hexahydrothiazolo[3′,4′:3,4]imidazo[1,2-a]quinazoline-5,11-diones. The relative configuration of C-6a and C-10a centres of the tetracyclic compounds obtained was assigned as trans on the basis of X-ray crystallographic study.     

Acylation of 6,7,8,9-tetrahydro-5<Emphasis Type="Italic">H</Emphasis>-[1,2,4]triazolo-[4,3-<Emphasis Type="Italic">a</Emphasis>]azepin-3-ylacetonitrile

6,7,8,9-Tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-ylacetonitrile reacts with carboxylic acid anhydrides and chlorides to afford acylation products at the nitrogen atom in the heteroring or methylene carbon atom, depending on the conditions and nature of the acylating agent. Heating of the N-acyl derivatives leads to migration of the acyl group with formation of C-acyl derivatives.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 12, 2004, pp. 1858–1860.Original Russian Text Copyright © 2004 by Makei, Volovenko, Nazarenko, Tolmachev.     

Unexpected o → n migration of the methyl group in 5-methoxy-6-cyanobenzimidazo-[1,2-a][1,8]naphthyridine

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 273–274, February, 1989.     

Pseudo-cross-conjugated mesomeric betaines 2. X-Ray crystallographic investigation of betaines based on quinoxaline derivatives

An x-ray crystallographic investigation of 3-methyl-5-cyanoimidazolio[1,21,6]pyrido[2,3 -b]quinoxalin-4-olate, which is a representative of a previously unknown type of polynuclear heterocyclic pseudo-crossconjugated mesomeric betaine, was undertaken.For Communication I, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1534–1538, November, 1992.