化学性质:结晶化合物,熔点高于140℃。
用途:作为维生素B2的中间体。
生产方法:以葡萄糖为原料,经过氧化、置换转化、置换酸化、内酯化和还原等步骤反应生成核糖酸。随后,在氢氧化钠参与下将核糖酸与2,6-二甲基苯胺缩合,并催化还原醛基,最终制得目标产品。
中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | D-ribonic acid-(3.4-dimethyl-anilide) | 64339-92-0 | C13H19NO5 | 269.298 |
—— | 3,4-xylidino-D-ribofuranoside | 111619-05-7 | C13H19NO4 | 253.298 |
中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
3,4-二甲苯基-6-苯基偶氮-D-核糖基胺 | N-<3,4-dimethyl-6-(phenylazo)phenyl>-D-ribitylamine | 21037-26-3 | C19H25N3O4 | 359.425 |
—— | 1-Deoxy-1-{[4,5-dimethyl-2-(phenyldiazenyl)phenyl]amino}pentitol | 21037-26-3 | C19H25N3O4 | 359.425 |
—— | 5-(N-nitroso-3.4-dimethyl-anilino)-L-ribo-pentanetetrol-(1.2.3.4) | 109278-14-0 | C13H20N2O5 | 284.312 |
—— | N-<3,4-dimethyl-2-(phenylazo)phenyl>-D-ribitylamine | 21037-25-2 | C19H25N3O4 | 359.425 |
A dilemma arises for researchers who sample hidden populations, such as injection drug users (IDUs), and use financial incentives to recruit respondents. To prevent respondent duplication (a subject participates in a study multiple times by using different identities) and respondent impersonation (a subject assumes the identity of other respondents), researchers must confirm their subjects' identities. Documentation, however, introduces sampling bias against those who lack such identification, or who wish to remain anonymous. Definitive forms of identification like photography and fingerprints introduce a bias against the more distrustful members of the population, and scanner-based biometrics can be expensive. Most research projects therefore rely on staff to recognize former respondents, but staff turnover and a large number of respondents compromise accuracy. We describe and assess quantitatively the accuracy of a method for subject identification based on a statistical principle, the interchangeability of indicators, in which multiple weak indicators combine to form a stronger aggregate measure. The analysis shows that observable indicators of identity (scars, birthmarks, tattoos, eye color, ethnicity, and gender) and five biometric measures (height, forearm lengths, and wrist widths) provide the basis for a reliable and easily administered method for subject identification.