Pyrolysis of 2-(N-phenyl carboxamidomethylthio) S-phenyl-l,3,4-oxadiazolaet ca 200°C in a sealed tube affords carbon dioxide, hydrogen sulfide, water, benzonitrile, benzamide, aniline, p-aminoacetophenone, indole, thioglycolic acid. 3-phenyl-2-thiohydantoin and 2-mercaptoquinazolinone. Furthermore pyrolysis of 2-(N-p-tolyl carboxamidomethylthio)5-phenyl-l,3,4-oxadiazolgei ve rise to analogous products. A free radical mechanism has been suggested to account for the obtained products

Rcaction of cinnamonitriles la, b with 3-aminophenol (2a) or resorcinol (2b) gave the corresponding bcnzo[b] pyran derivatives (3a-d). Compound (3a) reacted with benzaldehyde to yield monohenzylideneamino derivative 4. Also, reaction of (3a) with henzenesulsulphonyl chloride gave 2-amino-3-cyano- 4-phenyl-7-phenylsulphonylamido-4H-benzo[h]pyr(a6n) which, in turn, underwent some reactions to produce new benzo[b]pyrano[6.5-d]pyrimidine derivatives (7, 9) and (10).

Rcaction of cinnamonitriles la, b with 3-aminophenol (2a) or resorcinol (2b) gave the corresponding bcnzo[b] pyran derivatives (3a-d). Compound (3a) reacted with benzaldehyde to yield monohenzylideneamino derivative 4. Also, reaction of (3a) with henzenesulsulphonyl chloride gave 2-amino-3-cyano- 4-phenyl-7-phenylsulphonylamido-4H-benzo[h]pyr(a6n) which, in turn, underwent some reactions to produce new benzo[b]pyrano[6.5-d]pyrimidine derivatives (7, 9) and (10).

Rcaction of cinnamonitriles la, b with 3-aminophenol (2a) or resorcinol (2b) gave the corresponding bcnzo[b] pyran derivatives (3a-d). Compound (3a) reacted with benzaldehyde to yield monohenzylideneamino derivative 4. Also, reaction of (3a) with henzenesulsulphonyl chloride gave 2-amino-3-cyano- 4-phenyl-7-phenylsulphonylamido-4H-benzo[h]pyr(a6n) which, in turn, underwent some reactions to produce new benzo[b]pyrano[6.5-d]pyrimidine derivatives (7, 9) and (10).

2-Mercapto-S-phenylazo-4,6-dimethylpyridine-3-carbonitr(i3l)e reacts with halocompounds to give Salkylated derivatives (421-h) which upon treatment with sod. ethoxide in ethanol, the thienopyridines (5a-h) was obtained. Compound (5) converted into pyridothienopyrimidines (6a-e) or (7a,b) boiling with triethyl orthoformate or acetic anhydride. Also it can be converted into pyridothienotriazine (8ad) by treating with nitrous acid. Chloropyridothienopyrimidine (IOa,b) was obtained by refluxing compound 6a or 7a with POCI3.

Pyrolysis of 5-phenyl-2-benzylthio-1,3,4-oxadiazol(e1 ) by heating at ca. 250°C in a sealed tube gives rise to CO,, H,S, H,O, benzyl thiocyanate, benzonitrile, benzyl sulfide, aniline, benzamide, benzaldehyde, 2-mercaptoquinazolinone, dibenzyl, stilbene, and tetraphenylthiophene. Furthermore pyrolysis of 5-phenyl-2-phenacylthio-l,3,4-oxadiazol(9e) gives analogous results, besides phenancyl thiocyanate. Pyrolysis of 5(2-hydroxyphenyl)-2-benzylthio-1,3,4-oxadiazol(e1 1) gives 2-hydroxybenzonitrile, 5(2-hydroxypheny1)-I ,3,4-oxadiazole-2-thioia,n d 2-hydroxybenzamide, in addition to the previous obtained results. The mechanism of these results has been discussed

Pyrolysis of 5-phenyl-2-benzylthio-1,3,4-oxadiazol(e1 ) by heating at ca. 250°C in a sealed tube gives rise to CO,, H,S, H,O, benzyl thiocyanate, benzonitrile, benzyl sulfide, aniline, benzamide, benzaldehyde, 2-mercaptoquinazolinone, dibenzyl, stilbene, and tetraphenylthiophene. Furthermore pyrolysis of 5-phenyl-2-phenacylthio-l,3,4-oxadiazol(9e) gives analogous results, besides phenancyl thiocyanate. Pyrolysis of 5(2-hydroxyphenyl)-2-benzylthio-1,3,4-oxadiazol(e1 1) gives 2-hydroxybenzonitrile, 5(2-hydroxypheny1)-I ,3,4-oxadiazole-2-thioia,n d 2-hydroxybenzamide, in addition to the previous obtained results. The mechanism of these results has been discussed

Pyrolysis of 5-phenyl-2-benzylthio-1,3,4-oxadiazol(e1 ) by heating at ca. 250°C in a sealed tube gives rise to CO,, H,S, H,O, benzyl thiocyanate, benzonitrile, benzyl sulfide, aniline, benzamide, benzaldehyde, 2-mercaptoquinazolinone, dibenzyl, stilbene, and tetraphenylthiophene. Furthermore pyrolysis of 5-phenyl-2-phenacylthio-l,3,4-oxadiazol(9e) gives analogous results, besides phenancyl thiocyanate. Pyrolysis of 5(2-hydroxyphenyl)-2-benzylthio-1,3,4-oxadiazol(e1 1) gives 2-hydroxybenzonitrile, 5(2-hydroxypheny1)-I ,3,4-oxadiazole-2-thioia,n d 2-hydroxybenzamide, in addition to the previous obtained results. The mechanism of these results has been discussed