Heat yield

Other iron(If) salts include, notably the green sulphate heptahydrate FeS04.7H2O which on heating yields first the white anhydrous salt FeS04 and then decomposes ... 

When pyridine is treated with zinc dust and acetic anhydride, a type of reductive coupling occurs and the product is diacetyltetrahydrodipyridyl (I) this undergoes a curious change on heating yielding pyridine and a new diacetyl compound, 1 4 diacetyl 1 4-dihydropyridine (II). The latter is reduced by zinc and acetic acid to 4-ethylpyridine (III). 

Both the fermentation of hexose sugars to ethanol and carbon dioxide and the oxidation of ethanol to acetic acid are exothermic (heat yielding) processes (see Sugar). The first reaction is expressed as foUows ... 

Enclosed nitrate filaments can be thermally decomposed to silver by a simple heat treatment. In opposition to electron irradiation that fragments the filaments, the simple heating yields continuous metal nanorods (see Fig. 6 for a silver filament generated by a 60 min. treatment at 400°C, pressure lO Torr). 

Thiooarbamide.—This is an example of a reversible reaction, in which either ammonium-thiocyanate or thiouiea when heated yields the same equilibiium mi.xttue. It may bo shown by melting a little thiourea for a minute, when the presence of thiocyanate is indicated by the addition of P eCl,. 

In contrast to l-methyl-l//-azepine, which on heating yields a dimeric product, more highly substituted 1-methyl-l //-azepines, e.g. 1,2,4,7-tetramethyl-l //-azepine-3,6-dicarbonitrilc (20), undergo ring contraction to aminofulvenes, e.g. 21.126-244... 

Method A Conventional heating Yield (%) Method B Microwave irrad. Yield (%) ... 

Polyfunctionality of the reactants is not sufficient in itself to assure formation of polymer the reaction may proceed intramolecularly with the formation of cyclic products. For example, hydroxy acids when heated yield either lactone or linear polymer (or both),... 

Calcium hydrogen carbonate plus heat yields calcium carbonate plus carbon dioxide plus water... 

Heating of the pyrazolinyl-5-carboxylates 156 in dilute HC1 generated the bispyazolylpyrazines 157 (Equation 37). Prolonged heating yielded the decarboxylated derivatives <1997RRC1141, 1997PHA101>. 

Aldehydes can be condensed with 1,3-diketones to give vinylic diketones 39 (X = H) and /V-bromsuccinimide converts these into the bromides 39 (X = Br) which supply furans 40 when heated. Yields are poor if the product carries no 5-substituent.101... 

Bipyridinium ylides 133, generated in situ from 4,4-bipyridinium diquaternary salts 133, undergo 1,3-dipolar cycloaddition with activated alkynes under micro-waves, on KF-alumina in the absence of solvent, to give 7,7-bis-indolizines 134 in 81-93% yield (Scheme 9.40) [91]. The same reactions, when performed using benzene as a solvent under classical heating, yielded 7,7-bis-indolizine derivatives in yields of only 50-60% [92],... 

A chemical reaction in which a single compound serves as both oxidizing and reducing agent and is thereby converted into a more oxidized and a more reduced derivative e.g., a hypochlorite upon appropriate heating yields a chlorate and a chloride. 

Allyl ethers when heated yield allyl phenols (Claisen),... 

Scheme 3.2-20. Formation of 1,5-dicarba-c/oso- derivative 39c. Its methylation leads to 39b, pentaborane derivatives 39 (R = CH2CMe3) via and reaction with RC2U to 39d,e (b X = Me c hydroboration of a borylalkyne with HBCI2 to X — Cl, d R — CMe3 e R — Ph). give 40a, which on heating yields the chloro...

These results seem to suggest that by irradiation in alkylamines DNA (single stranded) can undergo a selective release of thymine, accompanied by strand scission. This has indeed experimentally been verified. Irradiation of calf thymus DNA in 5% aqueous n-butylamine gave a photoproduct that on heating yields 1-n-butylthymine (81MI1). 

The ring closure of 5-alkylated 3-mercapto-1,2,4-triazoles to thiazolo[3,2-h][l,2,4]triazoles was reported a long time ago. Thus, treatment of 131 with acetic anhydride/pyridine (heat) yields 132 (50BRP634951). 

Alkylation of thiazolo[3,2-fi][l,2,4]triazoles takes place at N(l). Treatment of 180 with 2-bromo-l-arylethanones (acetone, heating) yields 181 [94JAP(K)06/184165, 94TL4587]. 

The chlorine oxidation of 19 b under careful conditions can yield an unstable yellow powder, which on gentle heating yields the olefinic species 19c this is assigned structure 19e, the previously unisolated vp analogue of PtBrs (oS.OMe) (oS). 

The -ketoester (90) (R = Bu ) undergoes hydrolysis and decarboxylation on treatment with acid and subsequent heating, yielding the 5-acetonyl derivative (89). In contrast, when (90) (R = Et) is allowed to react with aqueous acid, the acetic acid (91) (R = H) is isolated (Scheme 22) <82M793>. Treatment of the methyl ester (91) (R = R = Me) with triethylamine and tosyl azide leads to the diazoester which was shown by IR and NMR spectroscopy to exist in the open chain form (93) and not the cyclic form (92) (Scheme 22) <92JHC713>. 

Barium carbonate decomposes to barium oxide and carbon dioxide when heated at 1,300°C. In the presence of carbon, decomposition occurs at lower temperatures. Barium carbonate dissolves in dilute HCl and HNO3 liberating CO2. Similar reaction occurs in acetic acid. The solid salts, chloride, nitrate and acetate that are water soluble may be obtained by evaporation of the solution. Dissolution in HF, followed by evaporation to dryness, and then heating to red heat, yields barium fluoride. 

Platinum dichloride forms complexes with ammonia, [Pt(NH3)4]Cl2, which on heating yields [PtCl2(NH3)2]. 

Potassium fluoride is prepared by dissolving potassium carbonate in excess hydrofluoric acid. Evaporation of the solution forms crystals of potassium bifluoride. The bifluoride on heating yields potassium fluoride ... 

Ring contractions of yet a different kind are observed with H- azepines of type (54), which on heating yield 6-substituted fulvenes as illustrated in Scheme 3 for the dicyano-1//-azepine (7lJCS(C)l237). Analogous reactions occur with 3//-3-benzazepines. 

While both hydrogenation and epoxidation reactions of (7) (and substituted forms) occur on the oxepin valence tautomer, cycloaddition reactions proceed more readily on the arene oxide form (where the diene is closer to planarity). Thus the dienophiles DM AD and maleic anhydride (MA) readily yielded [4 + 2] cycloadducts with (7) as shown in Scheme 22 (67AG(E)385). A similar type of singlet oxygen cycloaddition reaction gave an unstable endoperoxide (106) which upon heating yielded trans-benzene trioxide quantitatively (equation 14). (75JOC3743). 

Dichloro-tetrapyridino-rhodium Chloride, [Rh py4Cl2]Cl, is prepared by dissolving rhodium zinc in aqua-regia, and, after removal of acid, heating the aqueous solution with pyridine. On cooling, the pyridino-salt is deposited in yellow prisms. It melts when heated, yielding a black oil, and on further heating, metallic rhodium. 

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