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Book II of PiHKAL: A Chemical Love Story, by Alexander & Ann Shulgin #33: 2C-I
#33 2C-I: 2,5-Dimethoxy-4-iodophenethylamine; 25I

#33 2C-I SYNTHESIS: A mixture of 7.4 g phthalic anhydride and 9.05 g of 2,5-dimethoxyphenethylamine (see the recipe for 2C-H for its preparation) was heated with an open flame. A single clear phase was formed with the loss of H2O. After the hot melt remained quiet for a few moments, it was poured out into a crystallizing dish yielding 14.8 g of a crude solid product. This was recrystallized from 20 mL CH3CN, with care taken for an endothermic dissolution, and an exothermic crystallization. Both transitions must be done without haste. After filtration, the solids were washed with 2×20 mL hexane and air dried to constant weight. A yield of 12.93 g of N-(2-(2,5-dimethoxyphenyl)ethyl)phthalimide was obtained as electrostatic yellow crystals, with a mp of 109–111 °C. A sample recrystallized from IPA was white, with a mp of 110–111 °C. Anal. (C18H17NO4) C,H,N.

To a solution of 12.9 g N-(2-(2,5-dimethoxyphenyl)ethyl)phthalimide in 130 mL warm (35 °C) acetic acid which was being vigorously stirred, there was added a solution of 10 g iodine monochloride in 40 mL acetic acid. This was stirred for 1 h, while being held at about 30 °C. The reaction mixture was poured into 1500 mL H2O and extracted with 4×75 mL CH2Cl2. The extracts were pooled, washed once with 150 mL H2O containing 2.0 g sodium dithionite, and the solvent removed under vacuum to give 16.2 g of N-(2-(2,5-dimethoxy-4-iodophenyl)ethyl)phthalimide as yellow amber solids with a mp of 133–141 °C. This mp was improved by recrystallization from 75 mL CH3CN, yielding 12.2 g of a pale yellow solid with mp 149–151 °C. A small sample from a large quantity of IPA gives a white product melting at 155.5–157 °C.

A solution of 12.2 g N-(2-(2,5-dimethoxy-4-iodophenyl)ethyl)phthalimide in 150 mL hot IPA was treated with 6.0 mL of hydrazine hydrate, and the clear solution was heated on the steam bath. After a few minutes there was the generation of a white cottage cheese-like solid (1,4-dihydroxyphthalizine). The heating was continued for several additional h, the reaction mixture cooled, and the solids removed by filtration. These were washed with 2×10 mL EtOH, and the pooled filtrate and washes stripped of solvent under vacuum giving a residue which, when treated with aqueous hydrochloric acid, gave 3.43 g of voluminous white crystals. This, after recrystallization from 2 weights of H2O, filtering, washing first with IPA and then with Et2O, and air drying, gave 2.16 g 2,5-dimethoxy-4-iodophenethylamine hydrochloride (2C-I) as a white microcrystalline solid, with a mp of 246–247 °C. Anal. (C10H15ClINO2) C,H,N.

DOSAGE: 14–22 mg.

DURATION: 6–10 h.

QUALITATIVE COMMENTS: (with 0 mg) “I was present at a group meeting, but was only an observer. With zero milligrams of 2C-I, I was able to get to a delightful plus 2.5 in about five minutes after I arrived at your place, and absorbed the ambience of the folks who had actually imbibed the material. My level lasted about four hours and came down at about the same time as did the others. There were no after-effects experienced except for a pleasant languor.”

[Erowid] received several requests for clarification of this note. Alexander Shulgin confirmed that this experience was a contact-high from being near a group of people on 2C-I. He writes:

I realize that some readers think that Ann and I are the authors of all the commentaries but in reality they have come from many different authors.

I have dug around in my notes and have finally found the origin of the zero milligram comment. It was a group experiment with 2C-I. Two members of the group arrived after everyone else had started and decided not to make a late entry, simply enjoy being observers. They reported that one of them turned on almost immediately, and went up to a plus two and a half. Further into his research notes he wrote that he had “absorbed the ambience of the folks who had actually imbibed the material,” and this was transferred directly to PiHKAL. I hoped that this would make it obvious that it was a contact high, not a drug-induced high.

Alexander Shulgin, October 2004

[Erowid] hopes that clarifies the issue.

(with 15 mg) “Comfortable onset. Most notable are the visuals, patterning like 2C-B (Persian carpet type), very colorful and active. Much more balanced emotional character, but still no feeling of insight, revelation, or progress toward the true meaning of the universe. And at 5 1/2 hours drop-off very abrupt, then gentle decline. I would like to investigate museum levels.”

(with 16 mg) “There was an immediate alert within minutes. As usual, it was only an awareness, then nothing happened for a while. In retrospect, I see some type of activity or awareness within 40 minutes, which then builds up over time. The peak was at 2 hours and seemed to maintain itself for a while. Near the peak, there was some hallucinogenic activity, though not a lot. The pictures in the dining room had color and pattern movement that was fairly detailed. Focusing on other areas, such as walls or the outside of the house, produced little activity, though I tried. There was certainly a lot of color enhancement. There was also that peculiar aspect of the visual field having darkened or shadowed areas. These darker areas seemed to shift around to some degree. That aspect seems to be similar to 2C-B. I don’t think I was more than +2.5 at the peak. Coming down was uneventful. I was down within 6 hours. I had no problems driving home, nor were there any difficulties with sleep. There were no body problems with this material. I ate like a horse.”

(with 16 mg) “The 16 was a bit much, I realized, because my body was not sure of what to do with all the energy. Next time I’ll try 14 or 15. However, my conversations were extremely clear and insightful. The degree of honesty was incredible. I was not afraid to say anything to anyone. Felt really good about myself. Very centered, in fact. A bit tired at day’s end. Early bedtime.”

(with 20 mg) “I think there is slightly less than full immersion in the sensual, with this material, compared with 2C-B, but I suspect it’s more a matter of getting used to the language of 2C-I and the feelings—getting tuned to a slightly different frequency, really—rather than that the material is less sensual or less easy to use sensually. Just different frequency, and we are very, very used to 2C-B. Good on the body. Transition, for me, not as strongly dark as 2C-B. But it could certainly take a lot more exploring, if we were able to give the time (about 9 hours) to it. Next day: sleep excellent. Energy next day unusually good. Quite tired by evening.”

EXTENSIONS AND COMMENTARY: The frequent comparisons between 2C-I and 2C-B stem, without doubt, from a bit of chemical suggestion. The two compounds have structures that are truly analogous, in technical terms. In one, there is a strategically located iodine atom, and in the other, an identically placed bromine atom. These are directly above and below one-another in the periodic table. And what is particularly maddening to the synthetic diddler, is that they cannot be lengthened, or shortened, or squooshed around in any way. You can’t make a longer and narrower version of a bromine atom, as you can do with, say, a butyl group. You’ve got what you’ve got, like it or not. No subtle variations.

But, on the brighter side of the picture, you have a heavy atom here, and this atom is intrinsic to the central activity of the compound. So, these materials are naturals for radio-labelling experiments. 2C-I has been made radioactive with radio-iodine, but the most impressive findings have been made with the 3-carbon analog, DOI.

One quotation from an observer of a group experiment is enclosed; an experiment with zero milligrams being taken. This is a instructive observation of what has been called a contact high.

There is one Iodotweetio known. In Scrabble, would you challenge a word that had seven of its eleven letters as vowels? Especially if the vowels were, specifically, iooeeio? It sounds just a little like the noise coming out of Old McDonald’s farm. But a Tweetio there is, namely, the 2-EtO-homologue of 2C-I. This is 2-ethoxy-4-iodo-5-methoxyphenethylamine, or 2CI-2ETO. The hydrochloride salt was a white, crystalline product with a melting point of 175–175.5 °C. The threshold level of activity was seen at an oral dose of 5 milligrams, and the generated effects were completely dispersed in a couple of hours. Most interestingly, larger doses, of up to 50 milligrams orally, seem to produce no more intense an effect, but simply to stretch out this threshold for an additional couple of hours. At no level that has been tried, has 2CI-2ETO produced even a plus-two response.

Where else can one go, from 2C-I? The iodine is the fourth, and the last of the so-called halogens, at the bottom of the classical periodic table. But, thanks to the miracles that have accompanied us into the nuclear age, there is a fifth halide now known, Astatine. All of its isotopes are radioactive, however, and it seems unlikely that there will ever be an entry (other than this one) for 2,5-Dimethoxy-4-astatophenethylamine. What might be speculated as to its activity? Probably similar in potency to 2C-I, requiring maybe 10 or 20 milligrams. The duration would be dicey to measure, since the isotope with the longest known half-life is half decayed in about 8 hours, and the longest lived natural isotope (for those who insist on natural rather than man-made things) is half decayed in less than a minute. Two predictions would be pretty solid. You might have quite a job accumulating your 10 milligrams of Astatine, as the most that has so far been made at one time is only about 0.05 micrograms, approximately a millionth of the amount needed. And the second prediction? You would not survive the screaming radiation that would bombard you if you could get the needed 5 or 10 milligrams of radio-astatine onto that magic 4-position, and the resulting 2C-A into your tummy!

Page updated 19 May 2012 · This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License ·

About PiHKAL • info

This version of Book II of PiHKAL is based on the Erowid online version, originally transcribed by Simson Garfinkle and converted into HTML by Lamont Granquist. I drew also on “Tyrone Slothrop’s” (Unfinished) Review of PIHKAL to enumerate the many analogues mentioned in PiHKAL but not described at length. Still others remain to be added.

I have tried here to expunge any artifacts introduced by the earlier transcriptions and restore most of the typographic niceties found in the printed edition. I’ve also made minor changes to some chemical names in line with current nomenclature practice, and in the hope of aligning with more readers’ searches. Typically the change is little more than expanding a prefix and setting it in italics. The errata and changes page has further details.

Cautionary Note

“At the present time, restrictive laws are in force in the United States and it is very difficult for researchers to abide by the regulations which govern efforts to obtain legal approval to do work with these compounds in human beings.

“No one who is lacking legal authorization should attempt the synthesis of any of the compounds described in these files, with the intent to give them to man. To do so is to risk legal action which might lead to the tragic ruination of a life. It should also be noted that any person anywhere who experiments on himself, or on another human being, with any of the drugs described herein, without being familiar with that drug’s action and aware of the physical and/or mental disturbance or harm it might cause, is acting irresponsibly and immorally, whether or not he is doing so within the bounds of the law.”

Alexander T. Shulgin

Copyright Notice

The copyright for Book I of PiHKAL has been reserved in all forms and it may not be distributed. Book II of PiHKAL may be distributed for non-commercial reproduction provided that the introductory information, copyright notice, cautionary notice and ordering information remain attached.

Ordering Information

PiHKAL is the extraordinary record of the authors’ years exploring the chemistry and transformational power of phenethylamines. This book belongs in the library of anyone seeking a rational, enlightened and candid perspective on psychedelic drugs.

Although Sasha and Ann have put Book II of PiHKAL in the public domain, available to anyone, I strongly encourage you to buy a copy. We owe them—and there’s still nothing quite like holding a real book in your hands.

PiHKAL (ISBN 0-9630096-0-5) is available for US$24.50 (plus $10 domestic first-class shipping) from Transform Press.

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