5,5-dimethyl-1,3-dioxan-2-one

Conditions: temp:130.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 208 grams (2 moles) 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 295 grams diethyl carbonate, and 4.3 grams NaOCH3 was placed in a flask equipped with an 18-inch vigreux column and heated gradually to 130° C. About 230 ml ethanol was distilled. When the pot temperature reached 150°-160° C. excess diethyl carbonate was removed under reduced pressure. The resulting product was dissolved in benzene, washed with water, and concentrated. This product was recrystallized from ether and isolated as pure 5,5-dimethyl-1,3-dioxan-2-one. A 75 gram sample had a melting point of 108° C., very nearly matching that in the literature (109° C.). was placed in a flask equipped with an 18-inch vigreux column About 230 ml ethanol was distilled reached 150°-160° C. was removed under reduced pressure The resulting product was dissolved in benzene washed with water concentrated This product was recrystallized from ether

Conditions: temp:110.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 198 g (2.00 mol) phosgene were introduced over a period of 1,5 h at 0° to 5° C. into a suspension of 208 g (2.00 mol) 2,2-dimethylpropane-1,3-diol and 600 ml dry dichloromethane, followed by stirring at that temperature until the initially vigorous evolution of hydrogen chloride had abated. The discharge of phosgene was prevented by an effective reflux condenser (dry ice). The solvent was then removed in vacuo, 500 mg (0.2% by weight) imidazole and 500 ml toluene were added and the reaction was completed by slowly increasing the temperature to 110° C. until the evolution of hydrogen chloride had stopped (3 hours). Residues of hydrogen chloride were then removed by application of a low vacuum. Removal of the toluene and fractionation of the residue in vacuo left 121 g (93%) of a solid product (boiling point 142° to 146° C./10 mbar). Recrystallization from ethyl acetate gave 117 g (90%) of product (Mp. 108° to 109° C.). Further working up is unnecessary. The solvent was then removed in vacuo, 500 mg (0.2% by weight) imidazole and 500 ml toluene were added (3 hours) Residues of hydrogen chloride were then removed by application of a low vacuum Removal of the toluene and fractionation of the residue in vacuo left 121 g (93%) of a solid product (boiling point 142° to 146° C./10 mbar) Recrystallization from ethyl acetate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Examples of biodegradable polymer segments for use in the present invention may be selected from suitable members of the following, among others: (a) biodegradable polyester segments, including homopolymer and copolymer segments comprising one or more monomers selected from hydroxyacids such as glycolide, D-lactide, L-lactide, beta-hydroxybutyrate, beta-hydroxyvalerate, beta-malic acid, D-gluconate, L-gluconate, etc., and lactones such as epsilon-caprolactone and delta-valerolactone, etc., p-dioxanones (resulting in the formation of polyether esters), etc., for example, selected from the following segments: polyglycolide, poly-L-lactide (PLLA), poly-D-lactide, poly-D,L-lactide, poly(beta-hydroxybutyrate), poly-D-gluconate, poly-L-gluconate, poly-D,L-gluconate, poly(epsilon-caprolactone), poly(delta-valerolactone), poly(p-dioxanone), poly(lactide-co-glycolide) (PLGA), poly(lactide-co-delta-valerolactone), poly(lactide-co-epsilon-caprolactone), poly(lactide-co-beta-malic acid), and poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate), among others, (b) biodegradable polycarbonate segments, including homopolymers and copolymer segments comprising one or more carbonate monomers selected from trimethylene carbonate, tetramethylene carbonate, 2,2-dimethyltrimethylene carbonate, etc., for example, selected from the following segments: poly(trimethylene carbonate), poly(tetramethylene carbonate), poly(2,2-dimethyltrimethylene carbonate), poly(lactide-co-trimethylene carbonate) and poly(glycolide-co-trimethylene carbonate), among others, (c) polyorthoester segments formed by the transesterification between a diol and diethoxytetrahydrofuran, for example, those formed by the reaction of diols such as trans-cyclohexanedimethanol (tCDM), 1,6-hexane diol (1,6-HD), 1,12-dodecane diol (1,12-DL) etc.) with diketene acetals such as 3,9-bis(ethylidene 2,4,8,10-tetraoxaspiro[5,5]undecane) (DETOSU), and those formed by the polymerization of a triol with an orthoester, (d) polyanhydride segments such as homopolymer and copolymer segments comprising one or more monomers selected from malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid (SA), maleic acid, isophthalic acid (ISO), hexadecandioic acid (HDA), fumaric acid (FA), terephthalic acid (TA), adipic acid (AA), dodecanedioic acid (DD), erucic acid dimer (EAD), and bis(p-carboxyphenoxy)alkanes such as bis(p-carboxyphenoxy)methane, bis(p-carboxyphenoxy)propane (CPP), and bis(p-carboxyphenoxy)hexane, for example, polyanhydride segments selected from the following: poly(adipic anhydride), poly(suberic anhydride), poly(sebacic anhydride), poly(dodecanedioic anhydride), poly(maleic anhydride), poly(sebacic acid-co-fumaric anhydride), poly[bis(p-carboxyphenoxy)methane anhydride], poly[1,3-bis(p-carboxyphenoxy)propane anhydride], poly[1,6-bis(p-carboxyphenoxy)hexane anhydride] and poly[1,3-bis(p-carboxyphenoxy)propane-co-sebacic acid anhydride], among others; (e) poly(phosphazine) segments, and (f) poly(amino acid) segments, including homopolymer and copolymer segments comprising naturally occurring amino acids such as alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine and valine, as well as atypical amino acids such as lanthionine, 2-aminoisobutyric acid, dehydroalanine and gamma-aminobutyric acid, as well as synthetic amino acid sequences, for example, amino acid derivatives such as those comprising γ-benzyl-L-glutamate and ε-carbobenzoxy-L-lysine, for instance, a poly(γ-benzyl-L-glutamate) (PBLG) segment or a poly(ε-carbobenzoxy-L-lysine) segment, segments comprising dimers based on a deaminated hydroxyl amino acid and an alkyl or aromatic ester of a hydroxyl amino acid, particularly desaminotyrosyl-tyrosine alkyl and aromatic esters (abbreviated as DTR, where R stands for the specific alkyl or aromatic ester used) such as desaminotyrosyl-tyrosine ethyl ester (DTE), desaminotyrosyl-tyrosine butyl ester (DTB), desaminotyrosyl-tyrosine hexyl ester (DTH), desaminotyrosyl-tyrosine octyl ester (DTO), desaminotyrosyl tyrosine dodecyl ester (DTD) and desaminotyrosyl tyrosine benzyl ester, for example, tyrosine-based polycarbonate segments (e.g., copolymers formed by the condensation polymerization of phosgene and a diphenol selected, for instance, from ethyl, butyl, hexyl, octyl, dodecyl, and benzyl esters of desaminotyrosyl-tyrosine, among others), tyrosine-based polyarylate segments (e.g., copolymers of a diphenol and a diacid linked by ester bonds, with diphenols selected, for instance, from ethyl, butyl, hexyl, octyl, dodecyl and benzyl esters of desaminotyrosyl-tyrosine, among others and diacids selected, for instance, from succinic, glutaric, adipic, suberic and sebacic acid, among others), and tyrosine-, leucine- and lysine-based polyester-amide segments, for example, comprising a combination of a desaminotyrosyl tyrosine alkyl or aromatic ester, desaminotyrosyl tyrosine, and various diacids, for example, succinic acid and adipic acid, among others.

Conditions: temp:130.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 208 grams (2 moles) 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 295 grams diethyl carbonate, and 4.3 grams NaOCH3 was placed in a flask equipped with an 18-inch vigreux column and heated gradually to 130° C. About 230 ml ethanol was distilled. When the pot temperature reached 150°-160° C. excess diethyl carbonate was removed under reduced pressure. The resulting product was dissolved in benzene, washed with water, and concentrated. This product was recrystallized from ether and isolated as pure 5,5-dimethyl-1,3-dioxan-2-one. A 75 gram sample had a melting point of 108° C., very nearly matching that in the literature (109° C.). was placed in a flask equipped with an 18-inch vigreux column About 230 ml ethanol was distilled reached 150°-160° C. was removed under reduced pressure The resulting product was dissolved in benzene washed with water concentrated This product was recrystallized from ether

Conditions: temp:130.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 208 grams (2 moles) 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 295 grams diethyl carbonate, and 4.3 grams NaOCH3 was placed in a flask equipped with an 18-inch vigreux column and heated gradually to 130° C. About 230 ml ethanol was distilled. When the pot temperature reached 150°-160° C. excess diethyl carbonate was removed under reduced pressure. The resulting product was dissolved in benzene, washed with water, and concentrated. This product was recrystallized from ether and isolated as pure 5,5-dimethyl-1,3-dioxan-2-one. A 75 gram sample had a melting point of 108° C., very nearly matching that in the literature (109° C.). was placed in a flask equipped with an 18-inch vigreux column About 230 ml ethanol was distilled reached 150°-160° C. was removed under reduced pressure The resulting product was dissolved in benzene washed with water concentrated This product was recrystallized from ether