On the synthesis of novel spiroglucosides and fused ring heterocycles fromdiethyl alpha-acetamido-alpha-bromomalonate

Diethyl alpha-acetamido-alpha-bromomalonate 1 with thiocarbamides 2 and 4-s ubstituted thiosemicarbazides 8 give 2-alkyl/aryliminono-5-amino-5-carbetho xy-4-oxo-(3H)-thiazoles 3 and 2-alkyl/arylimino-6-amino-6-carbethoxy-5-oxo- (3H,4H)-1,3,4-thiadiazines 9 respectively. Compounds 3 and 9 with arylisoth iocyanate 4 afford spiro [4.4]nonane and spiro[5.4]decane derivatives. Thes e spiroheterocycles on reaction with 2,3,4,6-tetrabenzoyl-alpha-D-glucopyra nosyl bromide 6 give novel spiroglucosides. Also compounds 3 and 9 with hyd razine hydrate give fused pyrazolo[5,4-d]thiazole and pyrazolo[5,4-e]thiadi azine derivatives respectively. The characterisation of the products has be en done on the basis of spectral (IR, H-1 NMR, and C-13 NMR) data.