Ein optisch aktives Phospholen‐oxid

Synthesis and biochemical evaluation of benzoylbenzophenone thiosemicarbazone analogues as potent and selective inhibitors of cathepsin L

“…With the exception of 1,3-bis(2-fluorobenzoyl)-5-bromobenzene thiosemicarbazone 32 , which was isolated as the Z isomer and did not isomerize after standing in acetone for one week, the final products exist as an inseparable mixture of E/Z isomers in solution (As evidenced by 1 H NMR). Imines including thiosemicarbazones are well-known for their propensity to isomerize in solution under catalyzed 62-63 and non-catalyzed 64-65 conditions or from heating while in the solid state. 66 As an example, benzoylbenzophenone thiosemicarbazone 33 , after purification and drying, was isolated as a single isomer; however, the compound slowly isomerized in solution (Figure 4).…”

Hydrogenation of unsaturated carboxylic acids with alkanes by aluminum chloride catalysis

“…Resolution was accomplished by treatment of the racemic bromide salt (9)7 with silver (-f)-lO-camphorsulfonate and recrystallization of the diastereomeric salts utilizing a triangular scheme of recrystallization.8 The head fraction was recrystallized to give 7a of constant rotation and melting point (cf. Scheme I).…”

“…20 mmol), n-hexane (25 ml), and aluminum chloride (40 mmol) were refluxed during 4 hr to give 3-methylbutanoic acid(9), yield 72%. No starting material was present in the final acidic part of the reaction mixture.i v i d u a l n o t d i r e c t l y a s s o c i a t e d w i t h s c i t e i s p r o h i b i t e d .…”

Design, syntheses and applications of chiral transition metal complexes bearing phosphorus-containing ligands

“…As shown in Table 5.16, four of the 1 H NMR signals are unambiguously assigned to their respective protons. The X-ray structure suggests that it is likely for Me(1) to be located at C (10) and C (28). This assignment is supported by the ring-shielding effect, in which the protons on C 10 2C 28will be shielded by the central aryl ring, resulting in an upfield shift.…”

“…[27] Similarly, resolution can also rely on the presence of suitable functional groups on the precursors, such as compound 10, which involved formation of an ammonium salt with chiral BCSA (bromocamphorsulfonic acid). [28] The formation of covalent diastereomers are commonly encountered in literature. Precursors 11 and 14 undergo chemical transformation reactions with enantiopure PEA to form amides, [29] whereas compound 15 reacts with chiral camphanyl chloride to form an ester.…”