Conversion of thiobiurets to thiadiazolones and triazinones by oxidative cyclization

1-Aroyl-5-aryl-2-thiobiurets [2a-i] react with hydrogen peroxide in an acidic medium yielding the new 5-aroylamino-2-aryl-2H-1,2,4- thiadiazol-3-ones [3a-i]. On treatment with alkali, thiobiurets [2a- c] gave 6-aryl-4-thioxo-1,2,3,4-tetrahydro-1,3,5-triazin-2-ones [4a- c]. Structures of the new products were established by analytical and spectroscopic [IR, 1H-NMR and MS] results. A mechanism is proposed to explain the formation of compound [7]

convenient route for butyrolactone synthesis

It has been reported that gamma, gamma-diary l-gamma-butyrolactones have chemo-therapeutic activity on pathogenic viruses. This reported activity coupled with our interest in the chemistry of butyrolactones prompted us to report a convenient method for the synthesis of gamma, gamma-diary l-gamma-butyrolactones [VI alpha-c] This method involves ring opening of the diarylethylene oxide [la-c] followed by ring closure [a/, scheme. 1]. Hydrolysis of the products followed: by decarboxylation give gamma, gamma-diary l-gamma-butyrolactones in a better yield than their synthesis via stobbe condensation method .When ethyl chloroacetone is allowed to react with aryl magnesium-halides [Ar= Ph-,PhCH[2]-,m-tolyl], followed by dehydrohalogenation, 1,1-diarylethylene oxides [la-c] are formed

Behavior of dibromocarbene towards substituted aryl aliphatic olefine

It is worth mention to report from the present investigation and HMO calculations that the steric factors play a significant role in controlling the rate of dibromocarbene addition to tri- and tetra-aryl substituted ethylenes [1IOTA -P], a point which far too long lacked emphasis in the literature. Although, occasional references to steric hindrance in carbene addition have been reported but nevertheless, emphasis is more generally placed on electronic effects

Action of amines on 1-benzoyl -2-thiobiuret and its 5-phenyl derivative

Recently, it has been reported that l-benzoyl-2-thiobiuret [la] [yellow] which exists in the thione form [thio-lactam] cylices to 6-phenyi-1,2,3,4-[or 2,3,4,6-] tetrahydrothioxo- l,3,5-thiazine-2-one [II] on being treated with 4 N aqueous sodium hydroxide, whereas its phenyl derivative [Ib] gives on similar treatment 5-phenyl-2-thiobiuret [III]