RESUMEN
BACKGROUND: Enamines and their variant enamides as powerful and versatile synthons have attracted great attention in synthetic chemistry. Enamides display unique stability and reduce enaminic reactivity in view of the electron-withdrawing effect of N-acyl group. A great deal of satisfactory achievements in the synthesis and application of enamides has been made in recent years. Especially, tertiary enamides without N-H bond regarded as low reactivity of compounds in the past can act as excellent nucleophiles to react with electrophiles for the construction of various nitrous molecules. OBJECTIVE: This review focuses on recent advances on tertiary enamides in the synthetic strategies and applications including addition, coupling reaction, functionalization and electro- or photo-chemical reaction. CONCLUSION: Tertiary enamides as electron-deficient nucleophiles display a satisfactory balance between stability and reactivity to offer multiple opportunities for the construction of various functionalized nitrogencontaining compounds. Further exploration of the reactive mechanisms involved tertiary enamides and the development of novel and efficient transformations to generate ever more complex building blocks starting from tertiary enamides are particularly worth pursuing.
RESUMEN
OBJECTIVE: To assess the association of plasma homocysteine (Hcy) level and 66A/G and 524C/T polymorphisms of methionine synthase reductase (MSR) gene with essential hypertension (EH) in ethnic Uygurs and Hans from Xinjiang. METHODS: From September 2011 to July 2014, 199 Uyghur and 216 Han patients were collected, while 195 healthy Uyghur ethnics and 217 healthy Han ethnics were recruited as the controls. Polymerase chain reaction and restriction fragment length polymorphism (PCR-RELP) was adopted to detect the above polymorphisms. Enzyme immunological assay was applied to measure the levels of plasma Hcy. RESULTS: Compared with the control, plasma Hcy levels were significantly higher in EH group in both Uyghur and Han ethnics (P<0.05). In both ethnic groups, there were also significant differences in MSR 524C/T polymorphism between the patients and controls (Uyghur: chi-square=6.559, P=0.038; Han: chi-square=12.684, P=0.002). No significant difference was found in MSR 66A/G polymorphism between the patients and controls in both ethnic groups (P>0.05). Plasma Hcy level in those with a 66G/524C genotype was statistically higher than that with 66A/524T (P<0.05). After adjusting confounding factors such as gender and age, Logistic regression analysis indicated that age (OR=1.924, 95% CI:1.177- 3.164, P=0.009), obesity (OR=2.491, 95% CI: 1.584-3.920, P<0.01), hyperhomocysteine (OR=1.609, 95% CI: 1.016-2.548, P=0.043) were independent risk factors for EH in Uygurs, while age (OR=1.133, 95% CI: 1.010-81.272, P=0.033), hyperhomocysteine level (OR=3.894, 95% CI: 2.432-6.237, P<0.01), and obesity (OR=1.864, 95% CI: 1.141-3.046, P=0.013) were independent risk factors for EH in Han ethnics. No association was found between the polymorphisms and EH in Uygurs and Hans. CONCLUSION: Age, hyperhomocysteine and obesity were common independent risk factors for EH in both Uygur and Han ethnics from Xinjiang. The MSR 66G genotype can increase the plasma concentration of Hcy, while MSR 524T genotype may reduce it. MSR 524C/T TT genotype may be a protective factor for EH. MSR polymorphisms 66A/G and 524C/T are not independent risk factors for EH in Uygur and Han ethnics from Xinjiang.