Synthesis of a Novel C₂-Symmetric Guanidine Base

Development of Novel Chiral Urea Catalysts for the Hetero-Michael Reaction

“…These reactions were performed under Mendoza's conditions, [23][24][25][26] i.e., the ratio of 2, 3 and catalyst was 1 : 1 : 0.1, and the concentrations of the substrate 2 and 3 were set at 0.3 M in CDCl 3 . The accelerating activities of the catalysts for this hetero-Michael reaction were determined by measuring the t 1/2 (monitored by 1 H-NMR), and the results are summarized in Table 1.…”

“…[15][16][17][18][19][20][21][22] At the outset of our studies for developing new chiral urea and/or thiourea catalyst of the hetero-Micahel reaction, we investigated the reaction of pyrrolidine (2) with g-crotonolactone (3) in the presence of the simple ureas 5 and 7, 17) thioureas 6 and 8, 17) and guanidine 9 as catalysts (Fig. 2).These reactions were performed under Mendoza's conditions, [23][24][25][26] i.e., the ratio of 2, 3 and catalyst was 1 : 1 : 0.1, and the concentrations of the substrate 2 and 3 were set at 0.3 M in CDCl 3 . The accelerating activities of the catalysts for this hetero-Michael reaction were determined by measuring the t 1/2 (monitored by 1 H-NMR), and the results are summarized in Table 1.…”

Guanidines from ‘toxic substances’ to compounds with multiple biological applications – Detailed outlook on synthetic procedures employed for the synthesis of guanidines

“…Microwave-assisted synthesis of highly functionalized guanidines on soluble polymer support © 2012 Elsevier Ltd. 51 Synthesis of novel functionalized guanidines and their different reactions have also been extensively carried out by many research groups, employing different approaches. Including the synthesis of dicarbethoxyguanidine, [103] nitroguanidine, [104] nitrotriarylguanidines, [105] N 1 -(6 -Methoxy-8-quinolylaminoalkyl-)guanidines, [106] 1-(Alky1amino)-guanidines, [107] N-alkyl-N'-carboalkoxy guanidines, [108] guanidino diesters, [109] N-guanidino-modified arginines, [110] radioabeled guanidines, [111] pyranosyl nucleosides with guanidine functionality, [112] phosphinyl guanidines, [113] guanidinium chlorides, [114] phase transfer catalyzed alkylation of guanidines, [115] N-triflyl guanidines, [116] cyclic guanidines, [117], [70] monocyclic guanidines, [118] bicyclic guanidines, [25], [119] tricyclic guanidines, [120] tetracyclic guanidines, [121] macrocyclic guanidines, [122] and polycyclic guanidines. [123] …”

Guanidines in Organic Synthesis

“…The polycyclic systems with spiro rings such as 10 have been nominated as modified guanidines [23,24]. Murphy et al [24a,24c] prepared tetracyclic guanidines (Murphys guanidines) 10 by double sequential intramolecular cyclizations, as shown in Scheme 4.7.…”