Benzhydrylamine Derivatives

Benzhydrylamine Derivatives Attachment of piperazine nitrogen directly to a benzhydryl carbon leads to a pair of compounds which show vasodilator activity, and which should be useful in disease states marked by impaired blood circulation. Reaction of piperonyl chloride (18) with a mixture of piperazine and piperazine dihydrochloride leads to the monoalkylation product (19). (It may be supposed that the mixture of free base and salt equilibrates to the monobasic salt, thus making the second amine less nucleophilic.) Alkylation of 19 by means of benzhydryl chloride then... 

A much more useful approach is the cleavage of peptide-resins having a C-terminal amide bond to the solid support. The most common solid supports for the synthesis of peptide amides are benzhydrylamine derivatives,which liberate the peptide by acidolysis. Examples include the 4-methylbenzhydrylamine resin (pMeBHA resin, for the Boc/Bzl... 

Imines are generated in situ from A -Boc a-sulfonylamines, therefore the adducts are useful precursors for coupling with ArB(OH)2. Chiral benzhydrylamine derivatives are obtained when the Rh-catalyzed reaction is conducted in the presence of the pyrrolidinodiphosphine 98. ... 

Tritylamines can serve as both linkers and protective groups for aliphatic amines because, unlike benzhydrylamines, they do not usually undergo acylation when treated with activated acid derivatives. Tritylation of aliphatic amines is readily accomplished by adding excess amine to a support-bound trityl chloride. Illustrative cleavage reactions are listed in Table 3.21. 

On the basis of these results, we have developed the first method for the enantiose-lective synthesis of chiral /3-amino acid esters from achiral imines and ketene silyl acetals using BLA 28. The enantioselectivity of the aldol-type reaction is dramatically increased by using sterically bulky A-substituents. Condensation of the imine derived from benzhydrylamine occurs with high enantioselectivity (90 % ee) (Eq. 80). Furthermore, the best result (96 % ee) is achieved by use of a 1 1 (v/v) mixture of toluene and dichloromethane as solvents. Thus, excellent enantioselectivity (95 % ee or better) has been achieved in reactions of aromatic aldehyde-derived imines... 

On the other hand, deisopropylidenation of 56 gave 5-keto-D-glucose (58) whose reductive amination with benzhydrylamine gave a mixture of 1-deoxynojirimycin derivative 62 and the L-iditol diastereomer in a ratio of 96 4 (74%). Deprotection of 62 afforded 2 (Scheme 11). ° ... 

The first supports bearing primary anodno groups including the aminomethyl-polystyrene [270], benzhydrylamine (BHA) [271], and p-methylbenzhydryl-amine (MBHA) [272,273] resins 7a (Table 7) were developed initially for the synthesis of peptide amides. Because the carbocations derived from resins 7a are not especially stabilized, cleavage requires the use of a strong acid such as TFMSA or treatment with HF and usually requires an amide... 

The synthesis of novel enantiomerically pure C3-symmetric trialkanolamine ligand containing phosphoryl groups (211) involved opening the epoxide ring in diethyl 2,3-epoxypropylphosphonate with benzhydrylamine and benzylamine catalyzed by Cu2l2- Enantiopure O-ethyl (2-naphthyl)phosphonothioic acid shows excellent chiral recognition of racemic 1-phenylethylamine derivatives. ... 

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