Heteropolare Verbindungen, VI. Mitteil. Additionsprodukt des Piperidins mit 2‐Thion‐3‐phenyl‐4‐äthoxy‐tetrahydrochinazolin

General Scope of 1,4-Diastereoselective Additions to a 2(3H)-Quinazolinone: Practical Preparation of HIV Therapeutics

“…The dihydroquinazolinone 12 is crystallized from methanol to afford an 85% isolated yield of the desired diastereomer exclusively (absolute configuration confirmed by X-ray). Exposure of 12 to wet TFA at 18 °C causes complete deprotection within 1 h, affording an 80% yield of DPC 961 ( 1 ) 6c. Formic acid at 60 °C also induces ionization of the phenethyl group to transform 12 into DPC 961 ( 1 ) in 85% yield.…”

“…Extended imines of type 11 (Scheme ), known as substituted 2(3 H )-quinazolinones, are reported to be highly colored compounds ranging from yellow to red 6a,c this particular bright orange analogue bearing a trifluoromethyl group has proven too reactive for practical isolation.…”

“…Extended imines of type 11 (Scheme ), known as substituted 2(3 H )-quinazolinones, are reported to be highly colored compounds ranging from yellow to red 6a,c this particular bright orange analogue bearing a trifluoromethyl group has proven too reactive for practical isolation. Eventually, we found that 11 could be produced in a mixture of CD 2 Cl 2 and TEA- d 15 , with trifluoromethanesulfonic anhydride as the dehydrating agent.…”