https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

In this review, we highlight the use of organic photoredox catalysts in a myriad of synthetic transformations with a range of applications. This overview is arranged by catalyst class where the photophysics and electrochemical characteristics of each is discussed to underscore the differences and advantages to each type of single electron redox agent. We highlight both net reductive and oxidative as well as redox neutral transformations that can be accomplished using purely organic photoredox-active catalysts. An overview of the basic photophysics and electron transfer theory is presented in order to provide a comprehensive guide for employing this class of catalysts in photoredox manifolds.

Organic Photoredox Catalysis

A Fast Flexible Docking Method using an Incremental Construction Algorithm

4.2.8. Reductive Coupling 3109 5. Reaction of Aromatic Compounds 3110 5.1. Electrophilic Substitutions 3110 5.2. Radical Substitution 3111 5.3. Oxidative Coupling 3111 5.4. Photochemical Reactions 3111 6. Reaction of Carbonyl Compounds 3111 6.1. Nucleophilic Additions 3111 6.1.1. Allylation 3111 6.1.2. Propargylation 3120 6.1.3. Benzylation 3121 6.1.4. Arylation/Vinylation 3121 6.1.5. Alkynylation 3121 6.1.6. Alkylation 3121 6.1.7. Reformatsky-Type Reaction 3122 6.1.8. Direct Aldol Reaction 3122 6.1.9. Mukaiyama Aldol Reaction 3124 6.1.10. Hydrogen Cyanide Addition 3125 6.2. Pinacol Coupling 3126 6.3. Wittig Reactions 3126 7. Reaction of R,â-Unsaturated Carbonyl Compounds 3127

Organic Reactions in Aqueous Media with a Focus on Carbon−Carbon Bond Formations: A Decade Update

A hypothetical model of the active site of angiotensin-converting enzyme, based on known chemical and kinetic properties of the enzyme, has enabled us to design a new class of potent and specific inhibitors. These compounds, carboxyalkanoyl and mercaptoalkanoyl derivatives of proline, inhibit the contractile response of guinea pig ileal strip to angiotensin I and augment its response to bradykinin. When administered orally to rats, these agents inhibit the pressor effect of angiotensin I, augment the vasodepressor effect of bradykinin, and lower blood pressure in a model of renovascular hypertension.

https://science.sciencemag.org/content/sci/196/4288/441.full.pdf

Design of specific inhibitors of angiotensin-converting enzyme: new class of orally active antihypertensive agents

Stability constants have been measured for the formation of 1:1 complexes between eight divalent metal ions and six carboxylate anions. For each anion the stabilities of the complexes follow the or...

Stability constants for some 1 : 1 metal-carboxylate complexes

Merged mechanisms for hydride transfer from 1,4-dihydronicotinamides

Second-order rate constants (kNu) have been measured in aqueous solution (I= 0.1 mol dm –3, 25 °C) for the SN2 reactions of methyl 4-nitrobenzenesulfonate with ammonia, 41 primary amines, 20 secondary amines. 29 tertiary amines and 7 anionic nucleophiles. For the aminolysis reactions, Bronsted-type correlations of nucleophilicity with basicity require the classification of all amines in terms of strictly defined structural classes with βnuc in the range 0.15–0.39. Swain–Scott plots indicate that simple amines, water and other light-atom nucleophiles (hydroxide, azide and cyanide, anions) are five times more reactive than heavy-atom nucleophiles (thiosulfate, thiocyanate, iodide and bromide ions). For amine nucleophiles there is a close linear correlation (of slope 0.44, and including both primary and secondary amines) between log kNu for the aminolysis of methyl 4-nitrobenzenesulfonate and log kNu for amine addition to the 1-methyl-4-vinylpyridinium cation. This correlation demonstrates a close linear relationship between the Swain–Scott n parameter and Ritchie's N+parameter for amine nucleophiles in aqueous solution (N+= 2.1n– 4.3).

Nucleophilicity towards a saturated carbon atom: rate constants for the aminolysis of methyl 4-nitrobenzenesulfonate in aqueous solution. A comparison of the n and N+ parameters for amine nucleophilicity

Equilibrium constants have been measured at 25° for the formation of pseudobases from the 2-methyl-phthalazinium, 1-methylquinoxalinium, 1-methyl- 1,5-naphthyridinium, 6-methyl-1,6-naphthyridinium, 7-methyl-1,7-naphthyridinium, 1-methyl-1,8-naphthyridinium, 1-methyl-3-nitroquinolinium, and 2-methyl-4-nitroisoquinolinium cations. Ionization constants have also been obtained for ionization of some of these pseudobases to alkoxide anions. For each cation the site of hydroxide attack has been determined by comparison of the u.v. and p.m.r. spectra of the pseudobases, the corresponding methoxide adducts, and the lithium aluminum hydride reduction products. In all cases, except for the 1-methylquinoxalinium cation, only one major pseudobase species is present in solution, and ring-opening does not occur to any appreciable extent. The pseudobase of the 1-methylquinoxalinium cation exists in equilibrium with a considerable amount of its covalent hydrate from addition of water across the C3—N4 bond.

Quaternary Nitrogen Heterocycles. I. Equilibrium and Spectral Data for Pseudobase Formation by the N-Methyl Cations of Diazanaphthalenes

The acidity and keto–enol tautomerism of a series of symmetrical β-diketones (RCOCH2COR (1): R = methyl (a), phenyl (b), 3-pyridinyl (c), 4-pyridinyl (d), 3-(N-methyl)pyridinio (e), and 4-(N-methyl)pyridinio (f)) and two series of unsymmetrical β-diketones (RCOCH2COCH3 (7a–7f) and RCOCH2COC6H5 (8a–8f)) have been investigated in aqueous solution at 25 °C and ionic strength 0.1. Values of were measured spectrophotometrically, and the acidities of the enols were obtained from the analysis of the pH dependence of the buffer catalysis for the general acid-catalyzed protonation of the enolateconjugate bases. These data in turn allowed the calculation of the acidities of the keto tautomers and the equilibrium constants for enolization (KE = [Enol]/[Keto]). In general, KE is greater for the symmetrical ketones(1) than for the corresponding R-substituted unsymmetrical ketones (7 and 8). KE is much more sensitive to the nature of the R substituent in these three series of β-diketones than in the corresponding serie...

John W. Bunting

Papers

Stability constants for some 1 : 1 metal-carboxylate complexes

Merged mechanisms for hydride transfer from 1,4-dihydronicotinamides

Nucleophilicity towards a saturated carbon atom: rate constants for the aminolysis of methyl 4-nitrobenzenesulfonate in aqueous solution. A comparison of the n and N+ parameters for amine nucleophilicity

Quaternary Nitrogen Heterocycles. I. Equilibrium and Spectral Data for Pseudobase Formation by the N-Methyl Cations of Diazanaphthalenes

The acidity and tautomerism of β-diketones in aqueous solution