Aldehydes and primary alcohols can be converted to one-carbon homologated primary, secondary, or tertiary amides in two operational steps. The approach offers several unique features including compatibility with (hetero)aryl, alkyl, alkenyl, and racemizable chiral substrates, the ability to prepare Weinreb amides from aryl and unhindered aliphatic substrates, and the opportunity to employ unprotected amino acids as amine sources in the amidation step.
Versatile trichloromethyl carbinols can be prepared in one pot from primary alcohols by treatment with Dess-Martin periodinane (DMP) in CHCl(3) followed by introduction of commercially available 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). A modification of the method was used to convert chiral primary alcohol (R)-(-)-2,2-dimethyl-1,3-dioxolane-4-methanol to the corresponding trichloromethyl carbinol with complete stereochemical fidelity, despite the reactant proceeding through a base-sensitive aldehyde intermediate.
The associations between sleep duration and cardiovascular diseases (CVDs) have been explored in many observational studies. However, the causality of sleep duration and many CVDs, such as coronary artery disease (CAD), heart failure (HF), and stroke, remains unclear. In this study, we conducted a systematic meta-review and meta-analysis of the results of observational and Mendelian randomization (MR) studies to examine how sleep duration impacts the risk of CVDs. We searched articles published in English and before 10 September 2021 in PubMed, Web of Science, and Embase. The articles were screened independently by two reviewers to minimize potential bias. We combined the meta-analyses of observational studies and 11 MR studies and summarized evidence of the effect of sleep duration on the risk of CAD, HF, stroke, and cardiovascular and all-cause mortality. Results showed that (a) evidence is accumulating that short sleep duration is a causal risk factor for CAD and HF; (b) abundant evidence from observational studies supports that long sleep duration is associated with the risk of CAD, stroke, and mortality, and long sleep duration has no causal associations with stroke and CAD in the MR studies; the causation of long sleep duration and other CVDs should be further studied; and (c) emerging evidence indicates that an increase in hours of sleep is associated with a decreased risk of CAD. Finally, we discussed the underlying pathophysiological mechanisms underlying short sleep duration and CVDs and suggested that increasing sleep duration benefits cardiovascular health.
(Trichloromethyl)carbinols, which are formed in one operation from either alcohols or aldehydes, can be converted into primary alcohols in a Jocic‐type reaction involving LiBH4. The net result is a convenient two‐step, one‐carbon homologation of primary alcohols or a reductive one‐carbon homologation of aldehydes featuring a broad substrate scope. The method is step‐economical, and it nicely complements established one‐carbon homologation strategies.
In
this paper, the influence of Stefan flow on different reactivity coke
solution loss reaction (C
coke
+ CO
2
= 2CO) at
different temperatures were analyzed and compared to deeply understand
the mechanism of the coke solution loss reaction. Isothermal experiments
of carbon dioxide gasification with Coke A (low reactivity), Coke
B (medium reactivity), and Coke C (high reactivity), respectively,
were carried out at 1100–1300 °C. After calculation, it
is concluded that the external diffusion coefficients and the mass
transfer coefficients with Stefan flow of three kinds of coke were
decreased, and their minimum average deviations with and without Stefan
flow were 44.57/43.27/43.23 and 42.57/39.47/39.15%, respectively.
As the coke reactivity increased, the diffusion and mass transfer
capacity of carbon dioxide with Stefan flow in the boundary layer
decreased. The carbon dioxide concentration on the outer surface of
three kinds of coke with Stefan flow was less than that without Stefan
flow. The influence of Stefan flow on carbon dioxide concentration
on the outer surface of coke was increased with the increase of coke
reactivity. The area of carbon dioxide concentration region in the
three kinds of coke declined after modification, and the deviations
of the carbon dioxide concentration region area before and after modification
of three kinds of coke ranged from 6.62 to 22.85%, 7.74 to 25.17%,
and 8.62 to 26.74%. The influence of Stefan flow on the carbon dioxide
concentration region increased as coke reactivity increased.
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