27255-46-5Relevant articles and documents
Divergent 2-Chloroquinazolin-4(3H)-one Rearrangement: Twisted-Cyclic Guanidine Formation or Ring-Fused N-Acylguanidines via a Domino Process
Yan, Gang,Zekarias, Bereket L.,Li, Xiaoyu,Jaffett, Victor A.,Guzei, Ilia A.,Golden, Jennifer E.
, p. 2486 - 2492 (2020/02/13)
A highly efficient 2-chloroquinazolin-4(3H)-one rearrangement was developed that predictably generates either twisted-cyclic or ring-fused guanidines in a single operation, depending on the presence of a primary versus secondary amine in the accompanying diamine reagent. Exclusive formation of twisted-cyclic guanidines results from pairing 2-chloroquinazolinones with secondary diamines. Use of primary amine-containing diamines permits a domino quinazolinone rearrangement/intramolecular cyclization, gated through (E)-twisted-cyclic guanidines, to afford ring-fused N-acylguanidines. This scalable, structurally tolerant transformation generated 55 guanidines and delivered twisted-cyclic guanidines with robust plasma stability and an abbreviated total synthesis of an antitumor ring-fused guanidine (4 steps, 55 % yield).
211. Scope and Limitations of the Reductive Coupling of Aromatic Aldimine Derivatives with Formation of 1,2-Diarylethylenediamine Units, Using Low-Valent Titanium Reagents
Betschart, Claudia,Schmidt, Beat,Seebach, Dieter
, p. 1999 - 2021 (2007/10/02)
Besides the adducts from lithium amides to aromatic aldehydes, iminium salts, aminals, and N-silylimines of aromatic aldehydes are coupled by the black suspension obtained from TiCl4 and Mg turnings in tetrahydrofuran (THF).The 1,2-diarylethylenediamines with tertiary and primary amino groups thus obtained are formed with no or only moderate diastereoselectivity (products 4a-d (Scheme 2) and 5a-e (Scheme 3), respectively); the amine component may contain a strained ring or additional heteroatoms as in azetidin, bis(2-metoxyethyl)amine piperazine, morpholine, and thiomorpholine (products 6a-e; Table 1).By an in-situ procedure, ethylenediamines and propane-1,3-diamines with two secondary amino groups are cyclized with aromatic aldehydes to give exclusively trans-diaryl-substituted piperazine and perhydro-1,4-diazepine derivatives (products 7a-f; Table 2).Enantiomerically pure monocyclic trans,cis-5-alkyl-2,3-diaryl-piperazines and diazabicyclononanes and -decanes are obtained by employing suitable diamines prepared from the amino acids (S)-alanine, (S)-phenylalanine, (S)-proline, and from (S,S)- or (R,R)-cyclohexane-1,2-diamine, respectively (products 11a-i, 7e; Table 4).The configurations of all products are derived from the high-field NMR spectra, some of which are discussed in detail (Figs. 1 and 2, Tables 3 and 5); all new compounds are fully characterized by their physical data.Depending upon the structure of the components employed, the yields of purified products range from as low as 7percent to essentially quantitative.