Mercapto derivative methoxy

Hydroxy and mercapto substituents at the 3- and 5-positions can also exist in tautomeric forms (see Section 4.01.5.2) and can be alkylated at either the substituent or the ring nitrogen atom. 3-Methoxy groups are not replaced by nucleophiles, but both 3- and 5-alkylthio groups react readily, as does 3-methoxy-l,2-benzisothiazole. Alkylthio compounds can be oxidized to sulfoxides and sulfones, and the latter readily undergo nucleophilic replacement. All the hydroxy compounds react with phosphorus pentachloride to give the chloro derivatives. 

With Sulfur Nucleophiles N-Carboxy-protected aziridine-2-carboxylates react with thiols to give P-mercapto-ot-amino acid derivatives. The reaction is usually catalyzed by BF3 and the yields range from fair to excellent [15, 16, 108-111]. With N-unprotected 3-substituted aziridine-2-carboxylates, the ring-opening with thiols usually takes place with anti stereoselectivity, especially in the case of the C-3 aliphatic substituted substrates. In cases in which C-3 is aromatic, however, the stereoselectivity has been found to be a function of the substitution pattern on the aromatic ring 3-p-methoxy ph eri yl-su bs li In led aziridines 143a (Scheme 3.51) and... 

In the series of a-substituted nitrones, the a-methoxy nitrones are the most easily oxidized nitrone derivatives. The study of electrochemical behavior of acyclic a-methoxy-, a-amino-, a-cyano- and a-mercapto-nitrones has shown an irreversible one-electron oxidation of the nitrone group (429). 

Iodine of the 5-iodotricyclic 274 was capable of nucleophilic displacement by methoxy-, hydroxyl-, amino-, and mercapto groups. The rearrangement of [3,4- ]-derivatives by refluxing in formamide to [5,1 - ]-analogues is seen in Scheme 81. 

Nonracemic l-methoxy-3-sulfinyl-l,3-butadienes derived from 10-mercapto-isobomeol have been prepared by the cycloaddition of (15)-isobornyl-10-sulfenic acid to (Z)- and ( )-l-methoxybut-l-en-3-yne. High levels of asymmetric induction were observed for the cycloaddition in some cases [40]. 

The hydroxyl group of the l,2-dioxan-3-ols could be substituted by a methoxyl, acetoxyl, and chloro group [73,167[. The Grignard reaction of the 3-methoxy-l,2-dioxane-4-carboxylates afforded the corresponding alcohols [80]. Further, the 4-bromoacetyl-3-methoxy-l,2-dioxanes could also be converted by the reaction of acetamide, hydrazines, thiomeas, thioamides, 4-amino-5-mercapto-1,2,4-triazole, and 2-aminothiophenol into heterocycle-substituted 1,2-dioxane derivatives [167]. 

The Structures and Reactions of Hydroxy- and Mercapto-thiophens and their Simple Derivatives.—2-Hydroxythiophens can in principle exist in three tautomeric forms, the hydroxy-form (110) and the 3- (111) and 4-thiolen-2-one (111a) forms. During recent years a series of derivatives of the 2-hydroxythiophen system, substituted with halogen, methoxy, aryl, and... 

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