Vener

This venerable book was written in 1935, shortly after the birth of modern quantum mechanics. Nevertheless, it remains one of the best sources for students seeking to gain an understanding of quantum-mechanical principles that are relevant in chemistry and chemical physics. Equally outstanding jobs are done in dealing with both quantitative and qualitative aspects of the subject. More accessible to most chemists than Landau and Lifschitz. 

The venerable bireciprocal potential consists of a repulsive tenn A/t and an attractive temi -B/r with n > m. This potential fiinction was introduced by Mie [118] but is usually named after Leimard-Jones who used it extensively. Almost invariably, / = 6 is chosen so that the attractive tenn represents the leading dispersion tenn. Many different choices of n have been used, but the most connnon is n = 12 because of its computational convenience. The Leimard-Jones (12,6) potential can be written in tenns of the well depth (s) and either the minimum position or the zero potential location (a) as... 

Transfer the filtrate to a ceramic evaporating dish and heat on a water bath until a crystalline scum forms on the top. Cool the dish quickly then filter the mess on the vacuum Buchner to yield 96g of Methylamine Hydrochloride. Concentrate the filtrate once again to obtain a second crop of crystals, -IQg. Concentrate the filtrate a third time as far as possible using the water bath, then store the dish in a vacuum dessicator loaded with Sodium Hydroxide in the bottom for 24 hours. Add Chloroform to the residue left in the crucible to dissolve out Dimethylamine Hydrochloride (distill off the Chloroform to recover - good stuff) then filter on the venerable old vacuum Buchner funnel to yield an additional 20g of Methylamine Hydrochloride, washing the crystals in the funnel with a small poiiion of Chloroform ( 10mL). 

The path from squalene (114) to the corresponding oxide and thence to lanosterol [79-63-0] (126), C qH qO, cholesterol [57-88-5] (127), and cycloartenol [469-38-5] (128) (Fig. 6) has been demonstrated in nonphotosynthetic organisms. It has not yet been demonstrated that there is an obligatory path paralleling the one known for generation of plant sterols despite the obvious stmctural relationships of, for example, cycloartenol (128), C qH qO, to cyclobuxine-D (129), C25H42N2O. The latter, obtained from the leaves of Buxus sempervirens E., has apparentiy found use medicinally for many disorders, from skin and venereal diseases to treatment of malaria and tuberculosis. In addition to cyclobuxine-D [2241-90-9] (129) from the Buxaceae, steroidal alkaloids are also found in the Solanaceae, Apocynaceae, and LiUaceae. 

L-Dopa and Trimethoprim are two other dmgs that can be made from vanillin. u-Dopa is used for the treatment of Parkinson s disease Trimethoprim is an antiinfective agent used mainly for urinary tract infections and certain venereal diseases. Also, Mebeverine, an antispasmodic agent, and Verazide, a generic antitubercular agent, are dmgs that can be made from vanillin or its derivatives. 

It was treated as a venereal disease, with disastrous results. 

Later, in the 1890s, Arrhenius moved to quite different concerns, but it is intriguing that materials scientists today do not think of him in terms of the concept of ions (which are so familiar that few are concerned about who first thought up the concept), but rather venerate him for the Arrhenius equation for the rate of a chemical reaction (Arrhenius 1889), with its universally familiar exponential temperature dependence. That equation was in fact first proposed by van t HofT, but Arrhenius claimed that van t Hoff s derivation was not watertight and so it is now called after Arrhenius rather than van t Hoff" (who was in any case an almost pathologically modest and retiring man). 

Around 1930, in Ameriea, presumably with the early superchargers in mind, several metallurgists sought to improve the venerable alloy used for eleetric heating elements, 80/20 nickel-chromium alloy (nichrome), by adding small amounts of titanium and aluminum, and found significant increase in creep resistance. 

Materials chemistry is now served by a whole range of journals, ranging from the venerable Journal of Solid-State Chemistry and Materials Researeh Bulletin (already mentioned) to Materials Chemistry and Physies (which, interestingly, now incorporates The International Journal of the Chinese Soeiety for Materials Seienee... which appears to be distinct from the Chinese MRS) and Journal of Materials Chemistry (published by the RSC in London) - also Chemistry of Materials, published by the ACS. In France, Annales de Chimie Seienee des Materiaux is an offshoot of a journal originally founded by Lavoisier in 1789 (shortly before he lost his head). Journal of Materials Synthesis and Proeessing is an interesting periodical with somewhat narrower focus. 

In this listing of examples, I have excluded straight metallurgical journals and the many devoted to solid-state physics, such as the venerable Philosophieal Magazine and Physieal Review B. 

The Zincke reaction is an overall amine exchange process that converts N- 2,A-dinitrophenyl)pyridinium salts (e.g, 1), known as Zincke salts, to iV-aryl or iV-alkyl pyridiniums 2 upon treatment with the appropriate aniline or alkyl amine. The Zincke salts are produced by reaction of pyridine or its derivatives with 2,4-dinitrochlorobenzene. This venerable reaction, first reported in 1904 and independently explored by Konig, proceeds via nucleophilic addition, ring opening, amine exchange, and electrocyclic reclosure, a sequence that also requires a series of proton transfers. By... 

The Knorr synthesis is a venerable process that has found a number of useful synthetic... 

Over the years the venerable K-R reaction has been instrumental in constructing flavones for SAR programs and natural product synthesis. ... 

Derivatives of anthranilic acid have a venerable history as nonsteroid antiinflammatory agents. It is thus not surprising that the corresponding derivatives in which phenyl is replaced by pyridinyl show much the same activity. 

Though the therapeutic utility of aspiri n has been recognized for well over a century, this venerable drug was not classified as a nonsteroid antiinflammatory until recently. The first drug to be so classified was in fact, indomethacin (1), a very useful agent introduced... 

Hydrazinopyridazines such as hydralazine have a venerable history as anti hypertensive agents. It is of note that this biological activity is maintained in the face of major modifications in the heterocyclic nucleus. The key intermediate keto ester in principle can be obtained by alkylation of the anion of pi peri done 44 with ethyl bromo-acetate. The cyclic acylhydrazone formed on reaction with hydrazine (46) is then oxidized to give the aromatized compound 47. The hydroxyl group is then transformed to chloro by treatment with phosphorus oxychloride (48). Displacement of halogen with hydrazine leads to the formation of endralazine (49). ... 

Esters of tropine have a venerable place in medicinal chemistry. One such compound, cocaine, the object of some current interest, was the natural product lead which led eventually to most of today s local anesthetics. A distantly related analogue is prepared by reaction of tropine (132) with 3,5-dimethylbenzoyl chloride. This leads to an ester structurally related to another ]ii ominent natural product, atropine (133). The product, tropanaerin (134), is described as an iinti.serotonergic agent intended for antimigraine use [34]. 

Thiazide diuretics have a venerable history as antihypertensive agents until the advent of the angiotensin-converting enzyme (ACE) inhibitors this class of drugs completely dominated first line therapy for hypertension. The size of thi.s market led until surprisingly recently to the syntheses of new sulfonamides related to the thiazides. Preparation of one of the last of these compounds starts by exhaustive reduction of the Diels-Alder adduct from cyclopentadiene and malei-mide (207). Nitrosation of the product (208), followed by reduction of the nitroso group of 209,... 

Replacement of a benzene ring by its isostere, thiophene, is one of the more venerable practices in medicinal chemistry. Application of this stratagem to the NSAID piroxicam, gives tenoxicam, 136, a drug with substantially the same activity, nie synthesis of this compound starts by a multi-step conversion of hydroxy thiophene carboxylic ester 130, to the sulfonyl chloride 133. Reaction of that with N-methylglycinc ethyl ester, gives the sulfonamide 134. Base-catalyzed Claisen type condensation serves to cyclize that intermediate to the p-keto ester 135 (shown as the enol tautomer). The final product tenoxicam (136) is obtained by heating the ester with 2-aminopyridine [22]. 

Venerie, /. venereal disease, specif, syphilis, venerisch, a. syphilitic. 

It is worth pointing out that the stereochemistry of intermediate 147 at C-9 and C-10 is inconsequential since both positions will eventually bear trigonal carbonyl groups in the final product. The synthetic problem is thus significantly simplified by virtue of the fact that any or all C9-C10 diol stereoisomers could be utilized. A particularly attractive means for the construction of the C9-C10 bond and the requisite C8-C10 functionality in 147 is revealed by the disconnection shown in Scheme 41. It was anticipated that the venerable intermolecular aldol reaction could be relied upon to accomplish the union of aldehyde 150 and methyl glycolate (151) through a bond between carbons 9 and 10. 

The cis dihydroxylation of olefins (10—>11, Scheme 2), one of organic chemistry s most venerable reactions, was first reported by Makowaka in 1908.9 It is also one of the most useful reactions, since it converts an olefin, itself a pivotal functional group, to a vicinal diol, another pivotal functional group present in many natural products and unnatural molecules. The original dihydroxyl-... 

Saburov VV, Vener TI, Gilyarevsky SD, Ivanov SV (1988) 14th International Congress of Biochemistry, Prague, Vol 1, p 235... 

The cycloaddition between norbornadiene (23 in Scheme 1.12) and maleic anhydride was the first example of a /mmo-Diels-Alder reaction [55]. Other venerable examples are reported in Scheme 1.12 [56]. Under thermal conditions, the reaction is generally poorly diastereoselective and occurs in low yield, and therefore several research groups have studied the utility of transition metal catalysts [57]. Tautens and coworkers [57c] investigated the cycloaddition of norbornadiene and some of its monosubstituted derivatives with electron-deficient dienophiles in the presence of nickel-cyclo-octadiene Ni(COD)2 and PPhs. Some results are illustrated in Tables 1.4 and 1.5. 

In the autumn of 1907, he started to study chemistry at the Institute chaired by Adolf von Baeyer at the University of Munich, where he passed the first Verband s examination after three semesters. In 1909, he continued his studies at the University of Berlin, gaining his doctorate in 1911 under Emil Fischer. The subject of his doctoral dissertation was Syntheses of Certain New Glucosides. The tremendous personality of Emil Fischer left its mark on Helferich for the rest of his life. In conversation with Helferich, one was often aware of the great veneration he always felt for his tutor and mentor. 

Lactic acid in the vagina gives it an acidic pH (5.0) which together with other products of metabohsm inhibits colonization by most bacteria, except some lactobacilli, which constitute the commensal flora. Other types of baeteria are unable to establish themselves in the vagina unless they have become extremely specialized. These species of microorganism tend to be associated with venereal infeetions. 

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