Type F Syntheses

Type F Syntheses (C—N—C—S + C).—synthesis of 2-amino-thiazoles based on a corresponding thiophen synthesis (where NH is equivalent to CH) involves the reaction of an alkyl halide R CHaX with an iV-acyl-thiourea in the presence of base, and proceeds via intermediate (10).  

Type F (C—N—C—S + C) Syntheses.—Potassium salts of cyanodithio-iminocarbonates (17) react with two moles of a-halogeno-ketones or chloroacetonitrile in basic media to yield substituted 4-aminothiazoles (19). By first alkylating the reactants (17), thiazoles (22) bearing unlike substituents in positions 2 and 5 may be obtained by this route. In suitable examples, the postulated intermediates (18) and (21) may be isolated.  

OEthyl a-chlorothioacetate (24), readily accessible from ethyl a-chloro-orthoacetate and hydrogen sulphide in the presence of ferric chloride, is a bifunctional thioacylating agent of great usefulness in the synthesis of sulphur heterocycles. Its condensation with the potassium salt of 

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Type F syntheses form the 4,5-N-C bond. There are very few references to this type of synthesis for the few examples that are known see CHEC-II(1996). There have been no new reports of type F syntheses since the publication of CHEC-II(1996). 

Type F Syntheses of Thiazoles (C-N-C-S + C). Substituted 7V-thiocarba-molyformamidines R CSN=CR NMe2 react with allyl bromide to give an azavinamidinium salt, which, upon treatment with a base, gives an ethylidene-A -thiazoline (R = = Me2N R = H, R = morpholino). This last com-... 

Type F Syntheses (C-N-C-S + C). Enaminothiones, RCSN=CR2NR R3 (R=substituted amino,R2=H,Me,Et,NMe2,R =R2=Me,Et R1=H, R2=Ph,Me) react with ArCH-X or alkyl/arylCOCH5X (X=halogen) to form vari-... 

Kuehne, M.E., and Xu, F., Syntheses of strychnan- and aspidospermatan-type alkaloids. Part 10. An enantioselective synthesis of (-)-strychnine through the Wieland-Gumhch aldehyde, 7. Org. Chem., 63, 9427, 1998. 

Recently the total synthesis of mucronine-B (150) 147), of the 4(15)-mucronine-A-type, and zizyphine-A (27) 148), the major representative of the 5(13)-type, was achieved. Total synthesis of dihydro derivatives of cyclopeptide alkaloids was more fruitful dihydro-zizyphine-A and -B 149) of the 5(13)-type, dihydro-mauritine-A 150) of the 5(14)-amphibine-B-type and dihydro-zizyphine-G 151, 152) of the 4(14)-amphibine-F-type were synthesized. The total synthesis of the linear peptide alkaloid hexaacetyl-celenamide-A was also achieved (156) 153). 

TABLE 13.44 Summary of f-Factor Plan Year Breakdowns for Tamoxifen Syntheses Type f-Kernel f-Excess f-Aux f-Total Total Mass of 1 (kg) per Mt... 

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