SDS of cas: 591-54-8. So far, in addition to halogen atoms, other non-metallic atoms can become part of the aromatic heterocycle, and the target ring system is still aromatic. Compound: 4-Aminopyrimidine, is researched, Molecular C4H5N3, CAS is 591-54-8, about Synthesis of Dipeptide, Amide, and Ester without Racemization by Oxalyl Chloride and Catalytic Triphenylphosphine Oxide.
An efficient triphenylphosphine oxide-catalyzed amidation and esterification for the rapid synthesis of a series of dipeptides ((2S,2S)/(2S,2R))-RNHCH(R1)C(O)N(R2)CH(C(O)OR3)R4 [R = (tert-butoxy)carbonyl, (9H-fluoren-9-ylmethoxy)carbonyl, (benzyloxy)carbonyl; R1 = Me, Bn, [(acetamidomethyl)sulfanyl]methyl, (tert-butoxy)methyl, etc.; R2 = H; R3 = Me, t-Bu; R4 = 2-methylpropyl, propan-2-yl, Bn; R2R4 = -(CH2)3-], amides (S)-R5N(R6)C(O)C(R7)(CH3)C6H5 (R5 = 2-methylpropyl, 3,4-dicyanophenyl, pyridin-4-yl, 1-(tert-butoxy)-1-oxo-3-phenylpropan-2-yl, etc.; R6 = H; R5R6 = -(CH2)2N(Boc)(CH2)2-; R7 = H, Me) and esters (S)-(Fmoc)NHCH(R1)C(O)OR8 (R1 = Me, Bn; R8 = Me, Ph, cyclohexyl, etc.) is described. This reaction is applicable to challenging couplings of hindered carboxylic acids (S)-RNHCH(R1)C(O)OH, C6H5C(CH3)(R7)C(O)OH, and (S)-(Fmoc)NHCH(R1)C(O)OH with weakly nucleophilic amines ((S)/(R))-NH(R2)CH(C(O)OR3)R4, R5NH(R6) or alcs., R8OH giving the products in good yields (67-90%) without racemization. This system employs the highly reactive intermediate Ph3PCl2 as the activator of the carboxylate in a catalytic manner and drives the reaction to completion in a short reaction time (less than 10 min).
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