2,4 -arylthio

Arylthio-5-ethyl-4(5)-thiazolone derivatives (164, 165. and 166) have been prepared by treatment of rhodanine (163) with the appropriate aryldiazonium salts (Scheme 86) (395). 

Both 2- and 7-methylthiopyrido[2,3- f]pyrimidines have been oxidized to sulfoxides and sulfones with hydrogen peroxide or MCPBA, as have 2-arylthio derivatives in the... 

Benzo[6]thiophene, 2-(aryloxymethyl)-3-chloromethyl-synthesis, 4, 872 Benzo[6]thiophene, 2-arylthio-synthesis, 4, 931 Benzo[6]thiophene, 2-bromo-reaction with potassamide, 4, 829-830 synthesis, 4, 934 Benzo[6]thiophene, 3-bromo-Grignard reagents, 4, 831 reactions, 4, 830 synthesis, 4, 934 Benzo[6]thiophene, 4-bromo-synthesis, 4, 878, 934 Benzo[6]thiophene, 5-bromo-electrophilic substitution, 4, 797 Benzo[6]thiophene, 6-bromo-synthesis, 4, 878, 934 Benzo[6]thiophene, 5-t-buty 1-3-methyl-synthesis, 4, 880... 

Pyrido[3,2-d]pyrimidine, 2-arylthio-oxidation, 3, 211-212 Pyrido[3,2-d]pyrimidine, 4-bromo-reactions, 3, 215... 

Arylthio but not 2-arylthio groups in quinazolines can be replaced with hydroxide ion or alkylamines. 4-Alkylthio-2-alkyl (or aryl)-quinazolines are readily alkoxylated (65°, 1 hr, 80-90% yield) at the 4-position. Arylthio and alkylthio groups have been found to be poorer leaving groups than chloro in several azines. 

Dibenzo[/>,/]thiepin derivative (39) has been obtained by cyclization of 2-arylthio-5-nitrophenylpyruvic acid (38) in the presence of polyphosphoric acid 33>. The use of this Friedel-Crafts type reaction is restricted to the synthesis of the stable di- and tri-annelated thiepins such as 40 33), 41 7), and 42 34). 

Reaction of methyl 3-(dimethylamino)-2-isocyanoacrylate (Ri = Me) with acyl chlorides gave 2-acyl-4-(dimethylaminomethylene)-5(477)-oxazolones 375. ° The same reaction with arenesulfenyl chlorides gave either 2-arylthio-4-(dimethylami-nomethylene)-5(477)-oxazolones 376 or an unsaturated 5(477)-oxazolone 377 containing an imidazole at C-2 depending on the substitution present in the arenesulfenyl chloride. Nitroarenesulfenyl chlorides favored 376. ° ° Selected examples of 372, 375, and 376 are shown in Table 7.33 (Fig. 7.44 Scheme 7.121). 

Mit Raney-Nickel lassen sich auch 2-Alkylthio-472, 2-Arylthio-473 und 4(5)-Arylthio-imidazo-]e474,475 entschwefeln, deren Entschwefelung mit Salpetersaure oder Eisen(III)-chlorid nicht mogiich ist. 

Tab. 25 2-Alkylthio- bzw. 2-Arylthio-benzimidazole durch Alkylierung bzw. Arylierung von 2-Mercapto-benzimidazolens a 372...

Alkyl- or aryl-dibenzothiophenes are conveniently prepared from the 2-arylthio-cyclohexanones, which are readily cyclized and dehydrogenated to yield the respective 1-, 2-, 3- or 4-substituted dibenzothiophenes (382 equation 9 Section 3.15.2.3.2). More complex polycyclic systems are available, using suitable aryenethiols, such as naph-thalenethiols, and 2-bromo-l-tetralone to synthesize the appropriate 2-arylthio ketones. Diaryl sulfides can be converted to dibenzothiophene derivatives in satisfactory yields by photolysis in the presence of iodine (equation 10) (75S532). Several alkyldibenzothiophenes with substituents in the 2- and/or 3-positions were prepared in satisfactory yield by the condensation of dichloromethyl methyl ether with substituted allylbenzo[6]thiophenes (equation 11) (74JCS(P1)1744). 

A variety of substituted 3-aminobenzo[6]thiophenes have been obtained by ring closure reactions of nitriles (equation 57). Various o -cyanophenylthioacetyl derivatives, when treated with base, yield the 3-amino derivatives (Section 3.15.2.2.3). The benzonitriles may be obtained by displacement of the o-nitro group from o -nitrobenzonitriles (74JOC3440). 2-Arylthio-l-chloroenamines are cyclized to 3 -dialkylaminobenzo[6]thiophenes in the presence of Lewis acid catalysts (equation 58). The 1 -chloroenamines may be prepared from t-amides or ynamines <8lH(15)l 179>. 

Reaction of the chloro derivative 210 with thiourea gave the thiolo derivative 211 [88IJC(B)825]. Displacement of the chlorine in 212 with 2-chlorothiophenol formed 2-(arylthio)-l,2,4-triazolo[l,5-a]pyrimidine (213) (89EUP337232) (Scheme 39). 

Keywords 2-arylthio-3-methylcyclohex-2-en-l-one, inclusion complex, photocy-clization, thiolane Experimental procedures ... 

AIkylthio)allylritanium reagentS, RSCH=CHCH2TiL (l).9 The reagents are prepared by deprotonation of allylic alkyl (aryl) sulfides with sec- or r-butyllithium followed by addition of Ti(0-/-Pr)4 at - 78°. They can react with carbonyl compounds at the a- or "/-position. a-Adducts predominate in reactions with a- and /1-mono- and disubstituted sulfides, whereas /-adducts predominate in reaction with /-substituted sulfides. The a-adducts show high eryr/iro-selectivity. The products are useful precursors to alkenyl oxiranes and to 2-(arylthio)-l,3-butadienes. 

Enantioselective photocyclization of 2-(arylthio)-3-methylcyclohexan-l-ones (75) to dihydrobenzothiophene derivatives 77 was also achieved in inclusion crystals using chiral host molecules. Photoirradiation of the 1 1 inclusion crystals of 75g with (-)-12b as a water suspension gave the corresponding photocyclization product (+ )-m-77g of 82% ee in 83% yield. Similar photoirradiation of the... 

The important 2-alkylthio-2-arylthio-carbapenems are usually prepared by nucleophilic displacement of the ester group from the enol ester derived from 2-oxocarbapenam. This procedure is discussed in more detail in Section 2.04.7.2. An account of the procedure and an example of the reactivity of a thiocarbonyl group are given in CHEC-11(1996) <1996CHEC-II(1B)659>. No new examples of the reaction of a thiocarbonyl group in fused /3-lactams have been found. 

When 2-arylthio-2-chloro-l,3,2-diazaphosphetidin-4-ones 7a and 7b were reacted with O-nucleophiles such as hexafluoroisopropanol and 4-nitrophenol in the presence of triethylamine, substitution of the chlorine atom took place and the new phosphoranes 7c and 7d were formed (Equation 7 and Table 4) <1995ZFA2001>. An analogous reaction of 2-arylseleno-2-chloro-l,3,2-diazaphosphetidin-4-ones with 4-nitrophenol was investigated <1996ZFA1250>. Treatment of the chlorophosphorane 82 with thiophenol gave a mixture of products, from which the spirophosphorane 9 was isolated (Equation 8) <1995ZFA2001>. 

It was known that 2-arylthio-3-methylcyclohexen-l-ones 15 underwent photocyl-ization in solution via the thiocarbonyl ylide intermediates 16 to yield the dihydro-benzothiophene derivatives 17 [42]. However, asymmetric induction was difficult... 

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