1,2-Thiazetidine 1,1-dioxides reactions

Thermolysis of the thiadiazabicyclo[3.1.0]hexene 30, obtained from reaction of an azide with an isothiazole dioxide affords the 1,2-thiazetidine-1,1-dioxide 31, but in poor yield and as part of a three-component mixture <96T7183>. Isocyanates 32 are available in moderate yield <94ZOR1700>. 

Alkylidene sulfenes (75), generally prepared by the dehydrohalogenation of alkylsulfonyl chlorides, add readily to electron-rich multiple bonds. For example, with enamines, the thietane dioxide (e.g., 76) is formed diazoalkanes yield thiirane dioxides (episulfones) and imines (Schiff bases) afford 1,2-thiazetidine 1,1-dioxides. There are available numerous reviews of sulfenes, including cycloaddition reactions.102... 

P-Sultams.1 Reaction of 1 with imines and a base (usually pyridine) in THF results in 4-carbomethoxy-l,2-thiazetidine 1,1-dioxides (2) in 20-93% yield. All products have the trans-orientation. The N-unsubstituted P-sultams can be obtained by use of phenylselenenylethyl as the R group. This R group can be replaced by hydrogen in 70-90% yield by selenoxide elimination to an enamide, which is then treated with I2 and Na2S03.2... 

Reaction of 1,2-thiazetidine 1,1 -dioxides with nucleophiles by S-N bond cleavage 731... 

Table 7 Reaction of 3-amino-2H-azirine derivatives with 1,2-thiazetidin-3-one 1,1-dioxides <1996HCA2067>...

Reaction of the 1,2-thiazetidine 1,1 -dioxide 68 with the weaker Lewis acid, tin(iv) chloride, gives the CM-aziridine as a major product together with benzophenone (Equation 2). However, when the reaction is carried out on the /raor-isomer, it affords essentially benzophenone accompanied by a trace amount of the /ra r-aziridine <1998T8941>. 

A synthetic approach to /3-sultams containing a direct bond between a tri- or tetracoordinated phosphorus atom and the nitrogen atom of the 1,2-thiazetidine 1,1-dioxide ring has been realized by direct phosphitylation or phosphorylation at nitrogen. Unfortunately, attempts to synthesize N-phosphorylated /3-sultams by reaction with diethyl phosphorochloridate and diethyl phosphorobromidate, generated in situ from diethyl phosphate and carbon tetrachloride or carbon tetrabromide, failed. However, when the /3-sultam is treated with freshly distilled diethyl phosphorochloridite or tetramethylphosphorodiamidous chloride in the presence of triethylamine, the expected AHliethy I phosphite and iV-phosphorodiamidous /3-sultams 150 are obtained (Equation 10). /3-Sultams unsubstituted... 

The transamidation-like reactions of the 2-(aminoalkyl)-l,2-thiazetidin-3-one 1,1-dioxides 172 in the presence of (piperidinomethyl)-polystyrene give the ring-enlarged eight-membered products 13 in 42-87% yields (Equation 35 <1999HCA354>). To prove the exclusive attack of the amine at the carbonyl rather than at the sulfonyl group, compound 13 (R = Me) and its stmcture with an asymmetrically situated methyl substituent was then established by X-ray crystallography (see Section 14.08.3.1.5). 

Mueller, M. and Otto, H. H., Properties and reactions of substituted 1,2-thiazetidine 1,1-dioxides Synthesis of N-aminoalkylated 1,2-thiazetidine 1,1-dioxides, Arc/i. Pharm, 322, 515, 1989. 

An acidic solution of 2,4-dinitrophenylhydrazine reacts with N-p-chlorophenyl-sulfonyl-3-ethoxy-l,2-thiazetidine 1-oxide to give (80%) the bis-2,4-dinitrophenyl-hydrazone of glyoxal. The adduct of A-sulfinyl-p-chlorophenylsulfonamide with dihydropyran is inert to catalytic hydrogenation and bromination. Treatment of two l,2-thiazetidine-3-one 1-oxides (e.g., 421) with hydriodic acid results in ring-cleavage and loss of sulfur. They are not oxidized to 1,1-dioxides by peracetic acid, ° but m-chloroperbenzoic acid accomplishes this oxidation. The unstable adducts with ketene decompose to amides with loss of hydrogen sulfide and sulfur dioxide or may be trapped by reaction with aromatic amines as shown for thiazetidine 1-oxide 422.An aldol-type condensation has been reported for A -cyclohexyl-1,2 thiazetidine-3-one 1-oxide and p-(A(A"-dimethylamino)benz-aldehyde. " Sulfur monoxide is lost in the flash-vacuum thermolysis of 422a. ... 

The cycloaddition of A -sulfonyl amines (Af-sulfonyl imides) (e.g., 431 ) to alkenes gives 1,2-thiazetidine 1,1-dioxides. " The stereochemistry about the double bond of the alkene is preserved in the adduct, and a tight zwitterionic intermediate is favored. Considerable amounts of six-membered cyclic adducts also are formed in these additions. Yields vary from good to poor. Thermolysis of 432 yields sulfonyl amine 433 the higher reaction temperatures involving 433 enable less reactive alkenes such as cis-stilbene to be used successfully. The success of cycloadditions to enamines depends on the latter having no protons on the -alkene carbon or on an sp hybridized carbon attached to the a-position. ... 

A novel entry into 1,2-thiazin-3-ones (203) can be achieved by a base-catalyzed ring expansion of the 1,2-thiazetidine 1,1-dioxide (204). This reaction is initiated by a retro-Michael process leading to the a)S-unsaturated thioester (205), which cyclizes to the thiazinone (206). Thiophenoxide addition to (206) gives the heterocycle (203) in an overall yield of 90% (Scheme 41) <94LA251>. 

Hiraoka and Kobayashi212 have reported that phenylsulfene adds to various Schiff bases (127) to give a mixture of cis- and truns-l,2-thiazetidine 1,1-dioxides with the cis isomer predominating (equation 119). The preferential formation of the cis isomer in this reaction (equation 119) suggested to these authors that the reaction is a concerted... 

In addition to the above examples involving nitrogen (in Group V of the Periodic Table), a phosphorane analogue of a 1,3-thiazetidine 1,1-dioxide has been suggested as an intermediate in the reaction of alkylidene- and arylidene-triphenylphosphoranes with sulphenes derived from alkanesulphonyl fluorides. ... 

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