(WO9745492-A1)      Preparation of a compound comprises; (a) farming a mixture of: (i) a compound of formula (I) (ii) a compound of formula (II); where the molar ratio of the compound of (a) (i) to (a)(ii) is 0.5:1 or greater; and (iii) 50-90 wt.% of a solvents selected from ethanol, n-propanol, and/or isopropanol. The mixture is free of acid catalyst, (b) heating the mixture with agitation so that it forms an intermediate of formula (III). (C) cooling the mixture of step (b) to less than 30 C then isolating the intermediate by filtration; (d) washing the intermediate with solvent selected from ethanol, propanol and/or isopropanol; (e) forming another mixture from; (i) the first intermediate: (ii) squaric acid. The molar ratio of the fist intermediate to squaric acid is 2:1 to 1.7:1; (iii) a solvent selected from heptanol and/or octarol; (iv) a cosolvent selected from n-hexane, cyclohexane, and/or heptare; where the vd ratio of (e)(iii) to (e)(iv) is 60:40 to 90:10; and the total amount q (e) (iii) plus (e)(iv) is 60-95 wt.%; (v) sufficient water to initiate the reaction of the first intermediate and squaric acid on heating in step (f): (F) heating, with agitation, the second mixture to reflux until there is no more intermediate, giving a second intermediate of formula (IV) and opto removing water from the mixture via azeotrope; (g) cooling the mixture to 10-40 C; (h) isolating the second intermediate by filtration: (i) washing the second intermediate in ethanol to remove any removing octanol or heptanol, followed by washing in ethyl acetate to remove ethanol; (i) forming a mixture of: (ii) the second intermediate; and (ii) pyridine; containing 15-40 molar equivalents of pyridine. (K) forming a mixtre by adding with agitation, 4-6 molar equivalents of 2-8C aliphatic acid chloride to mixture (j). The mixture is kept below 50 C by; (i) cooling the mixture; (ii) controlling the rate at which aliphatic acid chloride is added to form a compound of formula (V). Essentially anhydrous conditions are maintained through steps (i) and (k). (L) isolating the compound of step (K) by adding an acetate ester selected from ethyl acetate, isopropyl acetate, amyl acetate, methyl acetate, propyl acetate and/or butyl acetate and an aqueous HCl solution. A compound pptes from the mixture. The molar equivalent of the aliphatic acid chloride of step (K) plus the molar equivalent of HCl of step (e) approximately equals the molar equivalent of pyridine of step (i). The wt. ratio of acetate ester plus water to pyridine is 3:1 to 8:1 and the wt. ratio of acetate ester to water is 0.5:1 to 2:1; (m) isolating the compound by filtration from the final mixture which is optionally warmed to solubilise any impurities prior to filtration; and (n) washing the compound with ethyl acetate followed by material in order to purify the compound. R' = -(CH2)n H n = 1-7.    USE -   Used in photothermographic products and other applications where IR absorbing materials are needed.    ADVANTAGE -   Preparation of the dyes is simple and cost effective. A good yield is obtained.    (EP912636-A1)      A method of making a cpd. comprises: (a) forming a first mixture comprising: (i) a cpd. of formula (I); (ii) a cpd. of formula (II) where the molar ratio of the cpd. of (a)(i) to the cpd. of (a)(ii) is 0.5:1 or more; and (iii) 50-90 wt.% of a solvent of ethanol, n- or isopropanol, or mixts., based on the total wt. of the first mixture; where the first mixture is free of acid catalyst; (b) heating the first mixture to react to form a first intermediate of formula (III) where the first mixture is agitated during step (b); (c) cooling the mixture of step (b) to a temp. below 30C and isolating the first intermediate by filtration from the mixture of step (b); (d) washing the first intermediate with a solvent of ethanol, (iso)propanol, or mixts.; (e) forming a second mixture comprising (i) the first intermediate; (ii) squaric acid; where the molar ratio of the first intermediate to squaric acid is 2:1-1.7:1; (iii) a solvent of heptanol, octanol, or mixts.; (iv) a cosolvent of n- or cyclohexane, heptane, or mixts.; where the vol. ratio of the solvent of (e) (iii) to the cosolvent of (e)(iv) is 60:40-90:10; and where the total amt. of the solvent of (e)(iii) plus the cosolvent of (e)(iv) in the second mixture is 60-95 wt.% based on the total wt. of the second mixture; (v) water, where the amt. of water added in step (e) is sufficient to initiate the reaction of the first intermediate and squaric acid upon heating in step (f); (f) heating, with agitation, the second mixture to reflux until consumption of the first intermediate stops to form a second intermediate of formula (IV) and opt. removing water from the mixture via azeotrope during step (f); (g) cooling the second mixture to a temp. of 10-40C; (h) isolating the second intermediate by filtration from the mixture of step (g); (i) washing the second intermediate in ethanol to remove any remaining octanol or heptanol, and washing the second intermediate in ethyl acetate to remove any remaining ethanol; (j) forming a third mixture comprising: (1) the second intermediate; and (2) pyridine; where 15-40 molar equivs. of pyridine are present in the third mixture based on the second intermediate; (k) forming a fourth mixture of 4-6 molar equivs. 2-8C aliphatic acid chloride added to the third mixture at not more than 50C by cooling or controlling addn. rate to form a cpd. of formula (V) in anhydrous conditions; (l) isolating cpd. (V) with acetate ester and aq. HCl soln. to form a final mixture from which cpd. (V) is pptd. where the molar equivs. of aliphatic acid chloride plus HCl equal the molar equiv. of pyridine; where the wt. ratio of acetate plus water to pyridine is 3:1-8:1; and where the wt. ratio of acetate ester to water is 0.5:1-2:1; (m) isolating the cpd. (V) by filtration from the final mixture opt. warmed to solubilise any impurities prior to filtration; and (n) washing cpd. (V) with ethyl acetate and methanol to purify cpd. (V).    USE -   Used for making organic solvent soluble squaraine dyes as antihalation and acutance dyes in photo-thermographic prods. and other uses requiring infrared absorbing materials, eg. xerographic photoreceptors, organic solar cells or optical recording media.    ADVANTAGE -   The soluble squaraine dye is easily isolated from the reaction mixture, using a simple cost effective method with a very mild esterification process in standard chemical processing equipment in a relatively short process time with high yield of dye obtd. directly from the reaction mixture in sufficient purity for imaging.    (JP2000511221-W)      A method of making a cpd. comprises: (a) forming a first mixture comprising: (i) a cpd. of formula (I); (ii) a cpd. of formula (II) where the molar ratio of the cpd. of (a)(i) to the cpd. of (a)(ii) is 0.5:1 or more; and (iii) 50-90 wt.% of a solvent of ethanol, n- or isopropanol, or mixts., based on the total wt. of the first mixture; where the first mixture is free of acid catalyst; (b) heating the first mixture to react to form a first intermediate of formula (III) where the first mixture is agitated during step (b); (c) cooling the mixture of step (b) to a temp. below 30C and isolating the first intermediate by filtration from the mixture of step (b); (d) washing the first intermediate with a solvent of ethanol, (iso)propanol, or mixts.; (e) forming a second mixture comprising (i) the first intermediate; (ii) squaric acid; where the molar ratio of the first intermediate to squaric acid is 2:1-1.7:1; (iii) a solvent of heptanol, octanol, or mixts.; (iv) a cosolvent of n- or cyclohexane, heptane, or mixts.; where the vol. ratio of the solvent of (e) (iii) to the cosolvent of (e)(iv) is 60:40-90:10; and where the total amt. of the solvent of (e)(iii) plus the cosolvent of (e)(iv) in the second mixture is 60-95 wt.% based on the total wt. of the second mixture; (v) water, where the amt. of water added in step (e) is sufficient to initiate the reaction of the first intermediate and squaric acid upon heating in step (f); (f) heating, with agitation, the second mixture to reflux until consumption of the first intermediate stops to form a second intermediate of formula (IV) and opt. removing water from the mixture via azeotrope during step (f); (g) cooling the second mixture to a temp. of 10-40C; (h) isolating the second intermediate by filtration from the mixture of step (g); (i) washing the second intermediate in ethanol to remove any remaining octanol or heptanol, and washing the second intermediate in ethyl acetate to remove any remaining ethanol; (j) forming a third mixture comprising: (1) the second intermediate; and (2) pyridine; where 15-40 molar equivs. of pyridine are present in the third mixture based on the second intermediate; (k) forming a fourth mixture of 4-6 molar equivs. 2-8C aliphatic acid chloride added to the third mixture at not more than 50C by cooling or controlling addn. rate to form a cpd. of formula (V) in anhydrous conditions; (l) isolating cpd. (V) with acetate ester and aq. HCl soln. to form a final mixture from which cpd. (V) is pptd. where the molar equivs. of aliphatic acid chloride plus HCl equal the molar equiv. of pyridine; where the wt. ratio of acetate plus water to pyridine is 3:1-8:1; and where the wt. ratio of acetate ester to water is 0.5:1-2:1; (m) isolating the cpd. (V) by filtration from the final mixture opt. warmed to solubilise any impurities prior to filtration; and (n) washing cpd. (V) with ethyl acetate and methanol to purify cpd. (V).    USE -   Used for making organic solvent soluble squaraine dyes as antihalation and acutance dyes in photo-thermographic prods. and other uses requiring infrared absorbing materials, eg. xerographic photoreceptors, organic solar cells or optical recording media.    ADVANTAGE -   The soluble squaraine dye is easily isolated from the reaction mixture, using a simple cost effective method with a very mild esterification process in standard chemical processing equipment in a relatively short process time with high yield of dye obtd. directly from the reaction mixture in sufficient purity for imaging.