Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 2913-97-5, name is N-(2-Oxoethyl)phthalimide, A new synthetic method of this compound is introduced below., Safety of N-(2-Oxoethyl)phthalimide
A series of acceptor aldehydes was used to study the scope of the reaction. Results of reactions with oc,a-disubstituted aldehyde acceptors are shown in Table 7, hereinafter.Reactions with 2-ethylbutyraldehyde, cyclohexanecarboxaldehyde (c-CgHnCHO) , andcyclopentanecarboxaldehyde (C-C5H9CHO), providedaldol products at 4 °C and these product aldehydes were transformed to the corresponding methyl esters in good yields (62-75 percent from Compound 1) with high enantioselectivities (94-98percent ee) (entries 1, 3, and 4). The diastereoselectivities of the aldol reactions were also high (dr = >10:1 to 15:1) . The diastereomeric ratio of the aldol products decreased by epimerization at C2 when the compounds were stored or when they were purified by silica gel columnchromatography. [See (9) (b) Notz et al. , J”. Org. Chem. 2003, 68, 9624. (c) Cordova et al., J. Am. Chem. Soc. 2002, 124, 1866.] The column chromatography did not completely separate the anti-and syn-isomers of Compound 3 from each other.The reaction with di-n-butylacetaldehyde, an aldehyde bearing a bulky group, was slow at 4 °C and was performed at room temperature (rt; entry 2). This case also provided the desired product with high enantioselectivity (93percent ee). The reaction with a-dimethoxy acetaldehyde, available in aqueous solution, afforded the desired aldol product with low diastereoselectivity, but 86percent ee in the presence of water (entry 5).Thus, the aldol reaction of Compound 1 was efficient for the synthesis of a broad range of enantiomerically enriched y-branched-p-hydroxy-ot-amino acid derivatives. Results for reactions illustrated in Scheme 2 are shown in Table 7, again only Compound 1 acted as the donor.Table 7aCompound 2entryRproductdr (anti:syn)D1CHEt22b>10:12’CH(nBu)22c10:13c-CsH-j-i2d15:14C-C5H92e14:15″CH(OMe)22f5:1Compound 3entryRproductdr (antksyn)”ee (percent)6Yield (percent)c1CHEt23b>10:194752’CH(nBu)23c7:193683C-CgHn3d5:198734C-C5H93e16:1989625hCH(OMe)23f1:186 (syn, 68)69a Unless otherwise noted, a mixture of Compound 1 (2 mmol), acceptor aldehyde (10-20 mmol), and L-proline(0.6 mmol) in N-methylpyrrolidone (NMP) (1 mL) was stirred at 4 °C for 16-48 hours for the aldol reaction. See Scheme 2. b Diastereomeric ratio of Compound 2 determined by XH NMR analysis of the reaction mixture without purification. c Isolated yields of Compound 3 (from Compound 1). d Diastereomeric ratio of Compound 3 after purification using silica gel column chromatography, determined by “”H NMR analysis. e Enantiomeric excess of anti-Compound 3 determined by chiral-phase HPLC analysis, except noted. f The reaction was performed at rt. 9 The ee of anti-Compound 2e was determined by HPLC analysis of the corresponding oxime prepared with O-benzylhydroxylamine. h The reaction mixture included water.
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.