Simple and efficient methodology to prepare guanidines from 1,3-disubstituted thioureas

A Facile One‐Pot Synthesis of 1,2,3‐Tri‐ and 1,1,2,3‐Tetrasubstituted Bis(guanidine)s from Bis(thiourea)s

“…The approach, which was established by Wang et al, employs CuCl in a mixture of acetonitrile and toluene and yielded bis(guanidine) 2a in 45 % yield after 64 h (Table , Entry 1). Using potassium dichloroiodate, as reported by Costa and co‐workers, did not lead to any conversion of bis(thiourea) 1a (Table , Entry 2). However, using mercury(II), lead(II), and lead(IV) oxide, respectively, afforded 2a in nearly quantitative yields.…”

“…The use of thioureas as starting materials for the preparation of guanidines is a facile strategy, as desulfurization can be achieved by using a variety of reagents such as copper(I) salts, mercury(II) oxide, KICl 2 , lead oxides, and ZnO . These protocols may also be applicable for the synthesis of multisubstituted bis(guanidine)s, and, thus, we investigated their applicability in the transformation of bis(thiourea) 1a and pyrrolidine into the related bis(guanidine) 2a (Table ).…”

Guanidine and Biguanidine Derivatives of Natural Chlorins: Synthesis and Biological Assessment

“…The reported synthesis method using di-Boc-protected thiourea and copper or mercury chlorides as catalysts [17][18] did not give satisfactory yields of the target product 2 (Table 6, Scheme 2). Apparently, this method has low efficiency because it requires that the reaction mixture be treated with a trifluoroacetic acid solution, hence the nitrogen atoms of the macrocycle and guanidine group are protonated, which significantly complicates the chromatographic purification of product 2.…”

Electrochemical NaI-mediated one-pot synthesis of guanidines from isothiocyanates via tandem addition-guanylation

“…1 In the present time, guanidines have been prepared from amines with various precursors such as amidine sulfonic acids, 4 pyrazole carboximidamides, 5 triflyl guanidines, 6 benzotriazole guanidines, 7 cyanamides, 8 carbodiimides, 9 isothioureas, 10 and thioureas. [11][12][13][14][15][16][17][18][19][20][21] Among them, thioureas 1 have found widespread use due to their ease of preparation and stability (Scheme 1b). This method involves treating thioureas with the corresponding amines in the presence of desulfurizing agents.…”