The hydrolysis product of neotame, N -(3,3-dimethylbutyl)- l -α-aspartyl- l -phenylalanine (DMBAP), was crystallized from water as an anhydrate with a melting point at 197○C with decomposition. Its crystal structure was determined by single crystal X-ray diffractometry. The crystal is orthorhombic with space group P 2 1 2_ 1 2 1 with Z =4 and one molecule per asymmetric unit. The cell constants are a =5.520 (2) Å, $b=10.608$ (5) Å and c = 31.92 (2) Å. The 13 C solid-state nuclear magnetic resonance spectrum of DMBAP is compared with those of neotame monohydrate and neotame methanol solvate.

The benzene and ethanol solvates of neotame crystallized from solutions of neotame anhydrate in benzene and ethanol, respectively. The crystal structures of the two solvates were determined by single-crystal X-ray diffraction using synchrotron radiation. The benzene solvate crystallizes in the monoclinic space group, P21, Z = 2, with one neotame molecule and one benzene molecule per asymmetric unit. The cell constants are a = 13.060 (6) Å, b = 5.582 (2) Å, c = 17.954 (9) Å, and β = 102.079 (15)°. The ethanol solvate crystallizes in the orthorhombic space group, P212121 with Z = 8 (Z′ = 2). The cell constants are a = 10.047 (4) Å, b = 17.001 (4) Å, and c = 28.948 (7) Å. Intermolecular hydrogen bonding among neotame molecules is evident in the two crystals. The benzene solvate has a nonpolar region containing the benzene molecules, with the benzene rings and alkyl chains of the neotame molecules.

Purpose. To determine the crystal structure of the neotame anhydrate polymorph G and to evaluate X-ray powder diffractometry (XRPD) with molecular modeling as an alternative method for determining the crystal structure of this conformationally flexible dipeptide.

Purpose. To study the relative thermodynamic and kinetic stabilities of neotame anhydrate polymorphs A, D, F, and G, and to develop a quantitative method for analyzing polymorphic mixtures of A and G by powder X-ray diffractometry (PXRD).

Purpose: To prepare, characterize, and compare polymorphs of neotame anhydrate.

The dehydration of neotame monohydrate was monitored at various temperatures by differential scanning calorimetry (DSC), thermogravimetry (TGA), hot-stage microscopy (HSM), powder X-ray diffractometry (PXRD), and (13)C solid-state nuclear magnetic resonance (SSNMR) spectroscopy. This work emphasizes kinetic analysis of isothermal TGA data by fitting to various solid-state reaction models and by model-free kinetic treatment. The dehydration of neotame monohydrate follows the kinetics of a two-dimensional phase boundary reaction (R2) at 40-50 degrees C with an activation energy of 75 +/- 9 kJ/mol, agreeing well with 60-80 kJ/mol from model-free kinetics. At a low heating rate in DSC and TGA, neotame monohydrate undergoes dehydration to produce anhydrate Form E, which then converts to anhydrate Form A, followed by the melting of A. Neotame monohydrate under dry nitrogen purge at 50 mL/min undergoes partial isothermal dehydration at 50 degrees C to produce neotame anhydrate Form A. When neotame monohydrate is heated very slowly from 50 to 65-70 degrees C over 24 h, pure Form A is obtained.

Selon l'invention, on modifie le gout et les proprietes physico-chimiques de N-[N-(3,3-dimethylbutyl)-L-α-aspartyl]-L-phenylalanine 1-methylester en utilisant des additifs d'acide hydrophobe. De tels additifs comprennent l'acide benzoique, l'acide valerique, l'acide acetique, l'acide nonoique, l'acide isobutyrique, l'acide cyclohexocarboxylique, l'acide cinnamique, l'acide anisique, l'acide caproique, l'acide isocaproique, l'acide tannique, l'acide citrique, l'acide malique, l'acide lactique, l'acide gluconique, l'acide bitartrique, l'acide fumarique, l'acide adipique et des derives de ces acides. L'invention concerne egalement des procedes de preparation de ces compositions, des produits alimentaires prepares a l'aide de celles-ci, ainsi que des procedes de preparation de ces produits alimentaires a l'aide de ces compositions.

The crystal structure of the methanol solvate (empirical formula: 2C 20 H 30 N 2 O 5 ·3CH 3 OH) of a new dipeptide sweetener, neotame ( N -(3,3-dimethylbutyl)-L-α-aspartyl-L-phenylalanine 1-methyl ester), has been determined. Crystal data: a = 9.8989(1), b = 18.1331(1), c = 27.5725(1) Å, orthorhombic, space group P 2 1 2 1 2 1 , with Z = 4. Each unit cell includes 8 neotame and 12 methanol molecules. Disorder exists in one neotame molecule and one methanol molecule. The crystals were characterized by the following techniques: hot-stage microscopy (HSM), Karl-Fischer titrimetry (KFT), powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), thermogravimetry (TGA), 13 C solid-state nuclear magnetic resonance (SSNMR) spectroscopy. Under HSM at a heating rate of 10°C/min in silicone oil, the sample melts at 64–84°C and liberates bubbles at 71–86°C. DSC in open pans shows two overlapping endotherms at 56 and 71°C, probably due to melting and desolvation, respectively. TGA in open pans shows 5.9% weight loss due to desolvation below 70°C. Under house vacuum (23 mm Hg) over phosphorus pentoxide at 23°C, the methanol solvate produces pure amorphous anhydrate, which converts to crystalline neotame monohydrate in the presence of moisture.

Neotame, an alkylated dipeptide consisting of L,L-stereochemistry, is a new high intensity sweetener being developed by the Nutrition and Consumer Products Sector of Monsanto. The three diastereoisomers of neotame, L,D; D,L; and D,D were synthesized and evaluated for sweetness by sensory testing. Only the L,L-isomer was found to be sweet. The three-dimensional structure of the L,L diastereoisomer determined from single-crystal x-ray analysis demonstrates that the compound exists in an "L shaped" conformation, previously proposed for the requirement of the sweetness ability by aspartyl-based dipeptide compounds. The confirmation of neotame in the solid state also demonstrates well-oriented hydrophobic and hydrophilic regions which likely account for the high sweetness intensity of this dipeptide compound.