Science paper Investigations into the polymorphic properties of N,N-dimethyltryptamine

Microchemical Journal 110 (2013) 146–157

Alain Gaujac a,b,c, James L. Ford b, Nicola M. Dempster b, Jailson Bittencourt de Andrade a,d,Simon D. Brandt b,

⁎a Universidade Federal da Bahia, Campus Universitário de Ondina, 40170-115 Salvador-Ba, Brazil
b Liverpool John Moores University, School of Pharmacy and Biomolecular Sciences, L3 3AF, Liverpool, United Kingdom
c Instituto Federal de Educação, Ciência e Tecnologia de Sergipe, Br 101, Km 96, 49100-000 São Cristóvão-Se, Brazil
d Instituto Nacional de Ciência e Tecnologia, Centro Interdisciplinar de Energia e Ambient
e Campus Universitário de Ondina, 40170-115 Salvador-Ba, Brazil​

Abstract
The powerful psychoactive features of N,N-dimethyltryptamine (DMT) have sparked the imagination of many research disciplines for several decades. One of the key chemical features associated with compound identity is the determination of melting points. The descriptions of both melting points and morphology associated with DMT free base have long been a source of interest and discussion, especially when considering that these values encountered in the scientific literature range dramatically between 38–40 °C and 73–74 °C, respectively. Such variations in reported melting points suggest that DMT may exist in two or more polymorphic forms and it was the aim of this study to examine the potential polymorphism of DMT via X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC), including fast scan DSC. DMT samples were prepared following extraction from Mimosa tenuiflora inner barks or by laboratory synthesis and then its crystals were recrystallized from solutions of the alkaloid using either hexane or acetonitrile. Irrespective of source, crystals originating from synthesis were predominantly white crystals obtained using crystallization from hexane, whereas yellow samples following recrystallization with acetonitrile. Irrespective of source or solvent, two polymorphs appeared to exist with melting points, determined by DSC, of 57 °C to 58 °C for Form I and 45 °C to 46 °C for Form II. Estimates for their enthalpies were 91.9 ± 2.4 J g− 1 for Form I and 98.3 ± 2.8 J g− 1 for Form II. Form II converted to Form I during DSC; conversion was thus prevented by fast scanning rates of 100 °C min− 1. A transition temperature (Tg) in the range − 21 °C (2 °C min− 1) to − 13 °C (100 °C min− 1) was determined depending on DSC scanning rate. Its closeness to the melting point indicates a tendency of Form II to convert to Form I on storage, a phenomenon that was also facilitated by grinding. This study indicates that the presence of differently colored DMT free base crystals obtained from recrystallization might also point towards the existence of polymorphs rather than just the presence of impurities.

 

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I asked AI what it makes of my DMT sample with 67 °C mp. Some of the stuff it was saying was citing my posts lol. But it also pointed out that 5-meo prisms have a sharp 67 °C mp.

Past researchers have measured DMT's mp up to 74 °C though, the study cites. So if this study is confirming two polymorphs at two lower melting points (45 °C and 57 °C), then shouldn't there be one or two more? Possibly at 67 °C or 74 °C.

Or could it be possible I whipped my DMT into 5-meo somehow?

 

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But it also pointed out that 5-meo prisms have a sharp 67 °C mp

Was there a source given for it, or have you corroborated that elsewhere?

 

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Was there a source given for it, or have you corroborated that elsewhere?

Our Wiki lists Trout's notes and TIHKAL as a source

"Melting Point: 66-67°C, 67-68°C, 69-70°C (Trout's notes and TIHKAL)"

Psychedelic Compounds Chemical and Physical Properties - DMT-Nexus Wiki

wiki.dmt-nexus.me

"The product obtained is described as nice colorless prisms having a melting point of 66-67°C."

EP3753923A1 - Recrystallisation of 5-methoxy-n,n-dimethyltryptamine (5-meo-dmt) in methyl tert.-butyl ether (mtbe) without adding an anti-solvent - Google Patents

Method of purifying 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is provided which comprises dissolving crude 5-MeO-DMT in a solvent at a temperature above room temperature, cooling the obtained solution to a temperature below room temperature to precipitate solid 5-MeO-DMT, separating the solid...

patents.google.com

"As the freebase, 5-MeO-DMT is a white solid with a melting point of 69.5°C."

A narrative synthesis of research with 5-MeO-DMT - PMC

5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a naturally occurring, short-acting psychedelic tryptamine, produced by a variety of plant and animal species. Plants containing 5-MeO-DMT have been used throughout history for ritual and spiritual ...

pmc.ncbi.nlm.nih.gov

"Melting Point 66 °C"

https://www.biosynth.com/p/D-5380/1019-45-0-5-methoxy-nn-dimethyltryptamine

 

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I was thinking about this sentence in this study:

"Its closeness to the melting point indicates a tendency of Form II to convert to Form I on storage, a phenomenon that was also facilitated by grinding."

Apparently when they ground up the crystal samples, it increased the DSC scan's measured ratio of Form I : Form II.

Crystals were used without further treatment for DSC and XRPD except where samples of the four products were ground to determine the effect of grinding on their physical nature. Grinding of DMT samples was undertaken manually using an agate mortar and pestle performed using two different grinding intensities; i) brief crush and light grind and ii) a sixty second, more intensive, grind.

The DMT samples were also analyzed at the fast scan heating rate (100 °C min−1) following grinding.

Sample preparations for XRPD analysis ideally include grinding of samples to decrease particle size and minimize preferential orientation of crystal lattices [26]. However, due to the low thermal stability of the Form II DMT polymorph, the incidental thermal energy introduced during mixing and grinding was found to alter the polymorph contents in the samples. This was verified by XRPD and fast scan DSC analysis (100 °C min−1) of untreated samples and subsequent to light grinding and more heavily ground samples. A decrease in the content of the meta-stable Form II DMT polymorph was observed in all four DMT samples following grinding treatments; the extent of decrease was related to the degree of grinding. Typical XRPD and DSC spectra from grinding experiments are provided in Figs. 8 and 9 respectively, from analysis of sample DMT Y1 and demonstrate the reduction in Form II in lightly ground materials and the apparent absence of the meta-stable form following a heavier grind. Such data also confirm the apparent instability of the Form II of DMT.

Can anyone explain this? They're suggesting that the heat from grinding friction is changing one polymorph into the other. How does that work though? The heat of grinding doesn't melt the crystals (I assume), but they get hot enough to physically reconfigure the whole lattice on a molecular level? Is there something special about grinding or could any source of heat cause it to switch polymorphs? Maybe the switch temp is dependent on particle size?