Thiourea thio urea

METHYL-l-(l-NAPHTHYL)-2-THIOUREA (Urea, l-methyl-l-(l-naphthyl)-2-thio-)... 

NjPtSioHg, Platinate(II), bis(pentasuIfido)-, bis(tetrapropylammonium), 21 13 NzPtSijHg, Platinate(IV), tris(penta-sulfido)-, diammonium, 21 12, 13 N2SCH4, Urea, thio-chromium(O) complexes, 23 2 N2SC2, Sulfur dicyanide, 24 125 N2SC4H6, 2H-Imidazole-2-thione, 1,3-di-hydro-1-methyl-cobalt complexes, 23 171 N2SCSH12, Thiourea, N,N,N methyl-... 

The thio analogs are similarly prepared by using carbon disulfide instead of phosgene. These compounds react as cyclic ureas and thioureas. 

Faneti/ole (122) is a biological response modifier with significant immunosuppressant activity It can be synthesized by conversion of 2 phen> lethylamine (120) with ammonium thio cyanate to the corresponding thiourea analogue 121 The synthesis of faneli/ole (122) concludes by thiazole nng formation of 121 by reaction with phenacylbromide Thus its synthesis involves use of the classic Hantzsch procedure in which a bromoacetone analogue and an appropriate thio urea denvative are reacted 143]... 

Treatment of a chiral amine with phosgene is the cheapest way to prepare symmetrical ureas [29]. Nevertheless, due to the toxicity and reactivity of that reagent, it can advantageously be replaced by triphosgene [30] or l,l -carbonyldiimidazole [31-34] or other derivatives such as l,l -carbonyldi-2(lH)-pyridinone [35]. This procedure can be extended to thiophosgene (Scheme 1) and its thio-analogues, such as l,l -thiocarbonyldi-2(lH)-pyridinone to produce thioureas [36] chiral diamines can thus be transformed into the corresponding monoureas or monothioureas. 

Curran[106] A/,A/ -diphenyl (thio)urea (10-100 mol%) first thiourea cat. Claisen rearrangements... 

Figure 6.3 Stereoselective, chiral thiourea derivatives of achiral benchmark thiourea organocatalyst N,N -bis [3,5-(trifluoromethyl)phenyl]thiourea 9 stereoselective hydrogen-bonding thiourea organocatalysts incorporating the privileged 3,5-bis(trifluoromethylphenyl)thiourea moiety. The (thio)urea catalyst structure is the leitmotif for the chapter organization.

Apart from the increased catalytic efficiency, this structure design produced two positive side effects. In contrast to monofunctional (thio)ureas, which exhibit low solubility in nonpolar solvents due to intermolecular hydrogen-bonding association, tertiary amine thioureas of type 12 revealed intramolecular hydrogen bonding between the amine group and the amide protons making these (thio)ureas soluble in nonpolar reaction media such as toluene. The analysis of the X-ray crystal-... 

C9-epi-122 98% conv. (99% ee) after 30h, respectively (Figure 6.40). This structure-efficiency relationship supported the results already published by the Soos group for quinine- and quinidine-derived thioureas (Figure 6.39) [278]. C9-epimeric catalysts were found to be remarkably more efficient in terms of rate acceleration and stereoinduction than the analogs of natural cinchona alkaloid stereochemistry. This trend was also observed for the corresponding (thio)ureas derived from DHQD as shown by the experimental results in Figure 6.40 [279]. 

In the presence of thiourea catalyst 122, the authors converted various (hetero) aromatic and aliphatic trons-P-nitroalkenes with dimethyl malonate to the desired (S)-configured Michael adducts 1-8. The reaction occurred at low 122-loading (2-5 mol%) in toluene at -20 to 20 °C and furnished very good yields (88-95%) and ee values (75-99%) for the respective products (Scheme 6.120). The dependency of the catalytic efficiency and selectivity on both the presence of the (thio) urea functionality and the relative stereochemistry at the key stereogenic centers C8/C9 suggested bifunctional catalysis, that is, a quinuclidine-moiety-assisted generation of the deprotonated malonate nucleophile and its asymmetric addition to the (thio)urea-bound nitroalkene Michael acceptor [279]. 

Ricci and co-workers introduced a new class of amino- alcohol- based thiourea derivatives, which were easily accessible in a one-step coupling reaction in nearly quanitative yield from the commercially available chiral amino alcohols and 3,5-bis(trifluoromethyl)phenyl isothiocyanate or isocyanate, respectively (Figure 6.45) [307]. The screening of (thio)urea derivatives 137-140 in the enantioselective Friedel-Crafts reaction of indole with trans-P-nitrostyrene at 20 °C in toluene demonstrated (lR,2S)-cis-l-amino-2-indanol-derived thiourea 139 to be the most active catalyst regarding conversion (95% conv./60h) as well as stereoinduction (35% ee), while the canditates 137, 138, and the urea derivative 140 displayed a lower accelerating effect and poorer asymmetric induction (Figure 6.45). The uncatalyzed reference reaction performed under otherwise identical conditions showed 17% conversion in 65 h reaction time. 

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