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The hetero‐Diels‐Alder reaction of the phenylthio‐activated N‐monoacyl‐ and N,N‐diacyl‐enamino ketones 8a‐c containing a methyl group at position 2 of the oxadiene with the electron‐rich dienophiles 9a‐c yields the exo/endo adducts 10a‐d and 11a‐d in 82–95% yield with the endo adducts as the main products. The enamino ketone 8d with a S‐ethyl group at C‐3 does not react. Hydrogenation of 11a with Raney nickel in THF leads to the desulfurized dihydropyran 12, whereas in MeOH gives stereoselectively the perhydrophthalimido derivative 13, which, after deprotection, yields the β‐methyl glycoside 14 of rac‐4‐deoxydaunosamine. Under similar conditions 10c is converted into the β‐ethyl glycoside 15 of rac‐N‐benzoyl‐4‐deoxyristosamine. Stereoselective hydroboration of 12 affords 17 and subsequent cleavage of the protecting group leads to the β‐methyl glycoside 18 of rac‐acosamine.

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Alkylation of 2‐morpholino‐cycloalken‐1‐carbothionic acid anilides 1 and 2 with 1,3‐dibromopropane in a two‐phase system leads to 1‐morpholino‐cycloalken‐3‐aryl‐tetrahydro‐1,3‐thiazine‐2‐ylidene 3 and 4. Reactions of 2‐morpholino‐cyclopenten‐1‐carbothionic acid anilides 5 and 3‐morpholinothiocinnamic acid anilides 8 with 1,2‐dibromoethane yield 1‐morpholino‐cyclopenten‐3‐aryl‐thiazolidine‐2‐ylidene 7 and 2‐(2′‐phenyl‐2′‐oxo‐ethylidene‐3‐aryl)thiazolidine 9, respectively. Alkylation of 1‐indanone‐ and 1‐tetralone‐2‐carbothionic acid anilides 11 and 12 with dihalogenoalkanes yield 1‐oxo‐indanylidene‐ and 1‐oxo‐tetralidenethiazolidines 14, 16 and tetrahydro‐1,3‐thiazines 15, 17, respectively.

Arylmethylenemalononitrile and conjugate nitroalkenes, being markedly electron deficient, are versatile Michael acceptors for conjugated addition with various compounds containing acidic hydrogen atoms. In majority of reactions the Michael adducts are reactive intermediates that undergo spontaneous cyclization to carbo- [l] or heterocyclic [Z, 31 compounds.Recently we have published the efficient synthesis of various heterocyclic systems that consisted in reactions of arylmethylenemalononitriles with carbanions derived from benzoyl(thioacetani1ide) [4], 1-H-benzimidazole-2-acetonitrile [S] and 1-0x0-cycloalkano-2-carbothioic acid anilides [6]. Continuing our study on application of P-keto acid anilides to the synthesis of heterocyclic compounds we report in this work the results of reactions of 1-0x0-indano-(1) and 1-oxo-1,2,3,4tetrahydronaphthalene-(2) carbothioic acid anilides with benzylidenemalononitrile 3 and (E) p-nitrostyrene (9).