Trifluorides, from carboxylic

Sulfur tetrafliioride/titanium tetrafluoride 1,1,1-Trifluorides from carboxylic acids s. 16, 606 SFJTiF COOH CFg... 

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

These reactions are most important for the preparation of acyl fluorides. Acyl chlorides and anhydrides can be converted to acyl fluorides by treatment with polyhydrogen fluoride-pyridine solution or with liquid HF at —10° C. Formyl fluoride, which is a stable compound, was prepared by the latter procedure from the mixed anhydride of formic and acetic acids.Acyl fluorides can also be obtained by reaction of acyl chlorides with KF in acetic acid or with diethyl-aminosulfur trifluoride (DAST). Carboxylic esters and anhydrides can be... 

Deshmukh et al. demonstrated that triphosgene can also be used to prepare dialkylcar-bamoyl azides from tertiary amines and sodium azide. Alternatively, acyl azides (e.g. 303) can be converted via a one-step procedure from carboxylic acids using bis(2-methoxyethyl)aminosulfur trifluoride (Deoxo-Fluor) (Scheme 3.46). ... 

Highly Branched Acids. These acids, called neoacids, are produced from highly branched olefins, carbon monoxide, and an acid catalyst such as sulfuric acid, hydrogen fluoride, or boron trifluoride. 2,2,2-Trimethylacetic acid (pivaUc acid) is made from isobutylene and neodecanoic acid is produced from propylene trimer (see Carboxylic Acids, trialkylacetic acids). 

Nakagome and co-workers effected the successful cyclization of N-ethyl-N-arylaminomethylenemalonates (749) in poly phosphoric acid, prepared from orthophosphoric acid and phosphorus pentoxide in polyphosphate ester (PPE), prepared from phosphorus pentoxide and anhydrous diethyl ether in chloroform in phosphoryl chloride on the action of boron trifluoride etherate on the action of acetic anhydride and concentrated sulfuric acid or on the action of phosphorus pentoxide in benzene [71GEP2033971, 71JHC357 76JAP(K) 18440]. Depending on the work-up process, l-ethyl-4-oxoquinoline-3-carboxylates (750, R1 = Et), l-ethyl-4-oxoquinoline-3-carboxylic acids (750, R2 = H) and 3-ethoxycarbonyl-4-chloroquinolinium iodides (751) were obtained. Only the cyclization of... 

Sodium borohydride does not reduce the free carboxylic group, but borane prepared from sodium borohydride and boron trifluoride etherate in tetrahydrofuran converts aliphatic acids to alcohols at 0-25° in 89-100% yields... 

Reduction of aromatic carboxylic acids to alcohols can be achieved by hydrides and complex hydrides, e.g. lithium aluminum hydride 968], sodium aluminum hydride [55] and sodium bis 2-methoxyethoxy)aluminum hydride [544, 969, 970], and with borane (diborane) [976] prepared from sodium borohydride and boron trifluoride etherate [971, 977] or aluminum chloride [755, 975] in diglyme. Sodium borohydride alone does not reduce free carboxylic acids. Anthranilic acid was reduced to the corresponding alcohol by electroreduction in sulfuric acid at 20-30° in 69-78% yield [979],... 

Hydrolysis of the ethyl ester proceeded smoothly using hydrochloric acid in acetic acid to give carboxylic acid 69 in 88% yield (Scheme 4.9). Previously, amines were allowed to react with the carboxylic acid core in hot DMSO to deliver the C7 products however, the difluoroborate 70, derived from the carboxylic acid 69, greatly increased the reactivity of the C7 position. Consequently, the displacement of the C7-F with amines was accomplished at lower temperature (Baker et al., 2004 Cecchetti et al., 1996 Domalaga et al., 1993 Ellsworth et al., 2005a,b Hu et al., 2003). In this event, the carboxylic acid was allowed to react with boron trifluoride to deliver difluroboronate 70 in excellent yield. The thus afforded borate ester reacted with A -methylpiperidine in DMSO in the presence of triethylamine at ambient temperature to furnish ( —)-ofloxacin (1, levofloxacin) in 56% yield. 

The gas chromatographic separation of acids present in plasticizers, apart from identifying volatile aliphatic carboxylic acids up to Ce, deals mainly with methyl esters. Carboxylic acids, present either as free acids or as alkali salts after saponification of the plasticizers, must be esterified. Conversion with methanol in presence of boron trifluoride (2) is recommended. But even better suited for plasticizer analysis is direct re-esterification of the plasticizers writh methanolic hydrochloric acid (2). 

In the event, iodolactonization of the carboxylate salt derived from the ester 458 afforded 459, and subsequent warming of the iodo lactone 459 with aqueous alkali generated an intermediate epoxy acid salt, which suffered sequential nucleophilic opening of the epoxide moiety followed by relactonization on treatment with methanol and boron trifluoride to deliver the methoxy lactone 460. Saponification of the lactone function in 460 followed by esterification of the resulting carboxylate salt with p-bromophenacylbromide in DMF and subsequent mesylation with methanesulfonyl chloride in pyridine provided 461. The diazoketone 462 was prepared from 461 by careful saponification of the ester moiety using powdered potassium hydroxide in THF followed by reaction with thionyl chloride and then excess diazomethane. Completion of the D ring by cyclization of 462 to the keto lactam 463 occurred spontaneously on treatment of 462 with dry hydrogen chloride. 

Compared with 49, 2,5-dioxabicyclo[2.2.2]octan-3-one (54) prepared from sodium 3,4-dihydro-2//-pyran-2-carboxylate has a much low polymerization reactivity [54] Lewis acids such as antimony pentachloride, phosphorus pentafluoride, and boron trifluoride etherate were not effective at all to initiate the polymerization of 54. Trifluoromethanesulfonic acid induced the polymerization of 54, but the yield and molecular weight of the polymer were low. Bicyclic lactone 54 was allowed to polymerize with anionic and coordination initiators such as butyl-lithium, lithiumbenzophenone ketyl, and tetraisopropyl titanate. However, the... 

Reaction takes place at 0-30° in the presence of boron trifluoride and mercuric oxide. The reaction is reversible in the presence of mercury salts and allows the preparation of vinyl esters from vinyl acetate and higher-molecular-weight carboxylic acids. ... 

Adamantane-2-earboxyUe acU. In a new, convenient synthesis of adamantane-2-carboxylic acid (4), adamantanone (1) is treated with dimethyloxosulfonium methylide to give 2-mcthyIeneadaman(ane epoxide (2). This is rearranged by treatment with boron trifluoride etheratc to the aldehyde (3, unstable). Oxidation with Jones reagent gives (4) in an overall yield of about 70% from (1). 

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