Table 1.

Reagents, their molar ratio, reaction conditions, specialized methods of purification and yields of O-acylderivatives of triterpenic oximes

Route no.	Reagents and their molar ratio	Reaction conditions	Specialized purification; yield	Ref.
1	Oxime 15: 0.5 mmol DMAP: 0.5 mmol 3,3-Dimethylglutaryl anhydride: 8–10 mmol	The mixture of reagents in dried pyridine was heated at 95 °C overnight	Column chrom. (silicagel, CHCl3 and acetone = 13:1); Yield of 16a: 59 %	Sun et al. (1998)
2	Oxime 20, 21 or 22: 1.0 mmol Carboxylic acid anhydride: 1.5 mmol Triethylamine: 0.4 ml	The mixture of reagents in dried benzene or diethyl eter was stirred for 4 h at room temp.	Column chrom. (Al2O3, CHCl3 and CH3OH = 10:1); Yields of 23a–23c, 24a–24c, 25a–25c 64–77 %	Flekhter et al. (2004)
3	Oxime 20: 1.0 mmol Carboxylic acid anhydride: 1.5 mmol DMAP: 0.2 mmol	The mixture of reagents in dried pyridine was refluxed for 12 h	Column chrom. (silicagel, CHCl3 and CH3OH = 99:1 or pure CHCl3); Yields of 23a and 23e–23 h: 63–86 %	Genet et al. (2010)
4	Oxime 24: 1.0 mmol 5-Phenyl-2,3-dihydrofuran-2,3-dione: 1.0 mmol	The mixture of reagents in dried toluene was refluxed for 30 min	No column chrom.; Yield of 26: 70 %	Nekrasov and Obukhova (2005)
5	Oxime 11: 1.0 mmol Adipoyl dichloride: 13.75 mmol	The mixture of reagents in dried THF was heated at 60 °C for 30 min	Twice column chrom. (1: RP-18, H2O and CH3OH, 2: silicagel, n-hexane and acetone = 9:1–7:3); Yield of 27a: 36 %	Ma et al. (2000)
	Oxime 12: 1.00 mmol Adipic acid: 9.25 mmol DCC: 2.50 mmol	The mixture of reagents in dried THF was stirred at room temp. for 3 h	Twice column chrom. (1: ODS, 2: silicagel, H2O and CH3OH = 1:1–100:0); Yield of 28a: 97.3 %
6	Oxime 11 or 12: 0.03–0.06 mmol Adipoyl-AZT: 0.07 mmol DMAP: 0.06 mmol DCC: 0.08 mmol	The mixture of reagents in dried THF was stirred at room temp. overnight	Column chrom. (ODS), next: HPLC (H2O and CH3OH = 20:80–0:100; Yields: 27b: 54.4 %, 28b: 58.1 %	Ma et al. (2002)
	O-acyloxime 28a: 0.02–0.05 mmol, DMAP: 0.03 mmol FK 3000: 0.02–0.05 mmol DCC:0.02–0.05 mmol	The mixture of reagents in dried methylene chloride was stirred at room temp. for 10 h	Twice column chrom. (1: RP-18, H2O and methanol = 3:7–0:1), 2: silicagel, n-hexane and acetone = 9:1–7:3); Yield of 28c: 55.7 %
7	First step: Oxime 30: 1.0 mmol Sodium acetate: 1.12 mmol Na2PdCl2: 1.11 mmol Second step: Crude product of first step: 1.00 mmol DMAP: 0.05 mmol Trietylamine: 0.64 mmol Third step: Compound 31 obtained earlier, Pb(CH3COO)4: 4.59 mmol NaBH4: 180 mg 1 N NaOH	First step: the mixture of reagents in acetic acid was stirred at room temp. for 72 h; Second step: the mixture of reagents in acetic anhydride and CH2Cl2 was stirred at room temp. for 45 min Third step: crude product was dissolved in dried THF and pyridine and stirred at room temp. for 15 min, next it the was cooled to −78 °C and the solution of Pb(CH3COO)4 in CH3COOH was added. After that solution was stirred for 15.5 h at room temp. Next, a solution of NaBH4 in 1 N NaOH solution was added and stirred at room temp. for 10 min	First step: no column chrom.; Yields of 31: no data; Second step: no purification; Third step: column chrom. (silicagel, n-hexane and ethyl acetate = 3:2; Yield of 32: 56 % in comparison to oxime 30	Honda et al. (2004)
8	Dioxime 39: 1.0 mmol DMAP: 0.2 mmol Acetic anhydride: 20 mmol	The mixture of reagents in pyridine was stirred at room temp. for 24 h	Column chrom. (silicagel, CH2Cl2 and CH3OH = 70:1); Yield of 41: 51 %	Hu et al. (2009)
9	Oxime 11, 12, 42 or 43: 1.0 mmol Carboxylic acid: 1.2 mmol DCC: 1.5 mmol	The mixture of reagents in dried dioxane or THF was stirred at room temp. for 30–90 min	No column chrom.; Yields of acylated oximes 44a–44 h, 45a–45 h, 46a–46 h and 47a–47 h: 86–96 %	Bednarczyk-Cwynar et al. (2011)
10	Oxime 12: 1.0 mmol Octanoic acid: 3.0 mmol DCC: 5.0 mmol	The mixture of reagents in dried THF was stirred at room temp. for 30 min	No column chrom.; Yield of 48: about 93 %	Bednarczyk-Cwynar et al. (2012a)
11	Oxime 11 or 49: 1.0 mmol Carboxylic acid: 1.2 mmol DCC: 1.4 mmol	The mixture of reagents in dried CH2Cl2 was refluxed for 8–14 h	Column chrom. (silicagel, petroleum ether with EtOAc); Yields of 50a–50j and 51a–51o: 70–93 %.	Zhao et al. (2013)
12	Oxime 53: 1.0 mmol Carboxylic acid: 1.2 mmol DCC: 1.5 mmol	The mixture of reagents in dried dioxane was stirred at room temp. for 30 min	No column chrom.; Yield of 54a–e: more than 90 %	Bednarczyk-Cwynar et al. (2012b)
13	Oxime 56: 1.0 mmol Acetic or propionic anhydride: 1.5 mmol DMAP: catalytic	The mixture of reagents in pyridine was refluxed for 4–6 h	Column chrom. silicagel (chloroform with methanol = 200:1); Yields of 57a and 57b: about 70 %	Liu et al. (2007)

DMAP 4-(N,N-dimethyl)aminopyridine, DCC dicyclohexylcarbodiimide, RP-18 reversed-phase with octadecyl carbon chain (C18)-bonded silica chromatography, ODS octadecylsilanyl chromatography, AZT azidothymidine, HPLC high-performance liquid chromatography