357666-75-2

Upstream product

• 700269-31-4 (3S)-5-ethoxy-3-methyl-1-phenethyl-3,6-dihydropyrazin-2(1H)-one 
• 118-92-3 anthranilic acid 
• 357666-51-4 (4S)-4-methyl-2-phenethyl-2H-pyrazino[2,1-b]quinazoline-3,6(1H,4H)-dione 

Downstream Products

• 420110-13-0 (+)-(1R,4S)-1-hydroxy-1,4-dimethyl-2-phenethyl-2,4-dihydro-(1H)-pyrazino[2,1-b]quinazoline-3,6-dione 
• 420110-14-1 (-)-(1R,4S)-1-hydroxy-4-methyl-2-phenethyl-1-phenyl-2,4-dihydro-(1H)-pyrazino[2,1-b]quinazoline-3,6-dione 

Relevant academic research and scientific papers

Intramolecular friedel-crafts-type reactions involving N-acyliminium ions derived from glycine templates

Enantiomerically pure 4-substituted 2-aralkyl-2,4-dihydro-1H-pyrazino[2,1-b]quinazoline-3,6-diones (1b-m) in which the alkyl chain is (CH2)n, n = 1-3, behave as glycine templates giving by treatment with [hydroxy(tosyloxy)iodo]benzene in ethyl acetate cis-1-tosyloxy derivatives. When these compounds contain electron-rich aryl substituents with n = 2, they spontaneously cyclize through intramolecular Friedel-Crafts-type diastereoselective reactions to give penta- or hexacyclic compounds. Otherwise, they give by solvolysis cis-1-alkoxy derivatives, which in a second step, may be cyclized in acid if n = 2, 3. All these reactions must occur through N-acyliminium species in SN1-like mechanisms. 1-Alkoxy-2-arylmethyl derivatives are reluctant to cyclize, giving trans-1-hydroxy compounds as the only isolated reaction products.

Cyclisation of (4S)-4-methyl-2-phenethyl-2,4-dihydro-(1H)-pyrazino[2,1-b]quinazoline-3,6- dione derivatives via N-acyliminium ions

Enantiomerically pure 1-methylene and 1-oxo derivatives (compounds 4 and 10, respectively) of compounds 1 were obtained and studied as precursors of N-acyliminium ions. 1-Substituted-1-hydroxyderivatives, obtained by regioselective syn-addition of organom