Efficient N-acyldopamine synthesis

Article abstract of DOI:10.1248/cpb.c16-00162

N-Acyldopamines are endogenous analogs of capsaicin that exhibit cannabinoid-like activities and were identified from brain extracts. Among them, N-arachidonoyldopamine (AADA) and N-oleoyldopamine (ODA) were characterized as transient receptor potential vanilloid type V1 channel (TRPV1) ligands. Recently, it was shown that N-acyldopamines may possess diverse physiological roles in addition to their ligand activities. To study the multiple functions and action mechanisms of endogenous N-acyldopamines, a simple and efficient method of N-acyldopamine synthesis was investigated. The eighteen potentially endogenous N-acyl-dopamines and two deuterated ones, N-palmitoyl dopamine-d₅ and N-stearoyl dopamine-d₅, were efficiently synthesized without protective groups in CH₂Cl₂ under optimized conditions using propylphosphoric acid cyclic anhydride (PPACA) as a condensation agent.

Full text of DOI:10.1248/cpb.c16-00162

Vol. 64, No. 7
Chem. Pharm. Bull. 64, 935–940 (2016)
935
Special Collection of Papers
This article is dedicated to Professor Satoshi Ōmura in celebration of his 2015 Nobel Prize.
Note
Efficient N-Acyldopamine Synthesis
,a
Yotaro Matsumoto,a,† Akihiro Ito,b,c Motonari Uesugi,d,e and Atsushi Kittaka*
a Faculty of Pharmaceutical Sciences, Teikyo University; Itabashi-ku, Tokyo 173–8605, Japan:
c
b Chemical Genetics Laboratory, RIKEN; 2–1 Hirosawa, Wako, Saitama 351–0198, Japan: Chemical
Genomics Research Group, RIKEN Center for Sustainable Resource Science; 2–1 Hirosawa, Wako,
d
Saitama 351–0198, Japan: Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto
e
University; Kyoto 606–8501, Japan: and Institute for Chemical Research, Kyoto University; Uji,
Kyoto 611–0011, Japan.
Received February 22, 2016; accepted April 11, 2016
N-Acyldopamines are endogenous analogs of capsaicin that exhibit cannabinoid-like activities and were
identified from brain extracts. Among them, N-arachidonoyldopamine (AADA) and N-oleoyldopamine (ODA)
were characterized as transient receptor potential vanilloid type V1 channel (TRPV1) ligands. Recently, it
was shown that N-acyldopamines may possess diverse physiological roles in addition to their ligand activi-
ties. To study the multiple functions and action mechanisms of endogenous N-acyldopamines, a simple and
efficient method of N-acyldopamine synthesis was investigated. The eighteen potentially endogenous N-acyl-
dopamines and two deuterated ones, N-palmitoyl dopamine-d5 and N-stearoyl dopamine-d5, were efficiently
synthesized without protective groups in CH2Cl2 under optimized conditions using propylphosphoric acid
cyclic anhydride (PPACA) as a condensation agent.
Key words N-acyldopamine; amide bond formation; cannabinoid type 1 receptor; endocannabinoid; transient
receptor potentioal vanilloid type 1 channel
N-Acyldopamines are members of the endocannabinoids
We investigated the reaction conditions for direct amide
and are present in nervous tissues and exhibit cannabinoid- bond formation between dopamine and fatty acid without any
like activities.1) N-Arachidonoyldopamine (NADA), an N- protective group, and we chose N-oleoyldopamine synthesis
acyldopamine, is known as a ligand for the cannabinoid type to establish a standard protocol consisting of: 1) condensation
1 receptor (CB1), but not CB2, and inhibits the N-arachi- agents, 2) amines, 3) solvents, and 4) addition order of the re-
donoyl-ethanolamine (AEA) transporter and fatty acid amide agents to the reaction flask (Chart 3).
hydrolase (FAAH) in the endogenous cannabinoid system.2)
1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochlo-
In addition, some N-acyldopamines including NADA and ride (EDCI)12) as the condensation agent always afforded
N-oleoyldopamine (ODA) act as agonists for the transient O-acylated products 3 and 4 with low yields of the target
receptor potential vanilloid type V1 channel (TRPV1), while amide 2 regardless of any combination of amine, solvent, or
N-palmitoyldopamine (PALDA) and N-stearoyldopamine procedures 1–3 (Table 1, entries 1, 2, 5–9). Benzotriazol-1-
(STEARDA) are nearly inactive as TRPV1 ligands3–5) (Chart
1). In addition to their ligand activities, recent studies suggest
that N-acyldopamines possess diverse biological and phar-
macological properties including anti-inflammatory and im-
munomodulatory activities,6,7) hypoximimetic activities,8) an-
tioxidant and neuroprotective activities,9) and anti-proliferation
activity against cancer cells.10)
NADA biosynthesis is considered to occur through direct
conjugation of arachidonic acid with dopamine,11) which sug-
gests that other endogenous N-acyldopamine species may exist
for a number of fatty acids. However, the range of commer-
cially-available N-acyldopamine species is limited. Here, we
report a simple and efficient theoretically-applicable method
for the synthesis of potentially all endogenous N-acyldopa-
mines without the use of protective groups (Chart 2).
† Present address: Graduate School of Pharmaceutical Sciences, Tohoku
University; Sendai 980–8578, Japan.
Chart 1. Structures of Representative Endogenous N-Acyldopamines
*To whom correspondence should be addressed. e-mail: akittaka@pharm.teikyo-u.ac.jp
© 2016 The Pharmaceutical Society of Japan

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Chem. Pharm. Bull.
Vol. 64, No. 7 (2016)
Chart 2. N-Acyldopamine Synthesis
Chart 3. N-Acyldopamine Synthetic Procedures Tested
yloxytris(dimethylamino)phosphonium
hexafluorophosphate purification step to yield pure N-acyldopamine in the small-
(BOP)13) showed the same efficacy as EDCI (entry 4). How- scale synthesis.
ever, propylphosphoric anhydride (propylphosphoric acid
Most of these analogs increased hypoxia inducible factor-1α
cyclic anhydride, PPACA)4) gave 2 exclusively (entry 3); expression, like the known endogenous N-acyldopamines.8)
therefore, this condensation agent was tested for further in-
vestigation using procedures 1 and 3 (entries 10–17). The best
Conclusion
condition for the selective N-oleoyldopamine (2) synthesis
The eighteen potentially endogenous N-acyldopamines and
is shown in entry 13, i.e., dopamine·HCl 1eq, PPACA 1eq, two deuterated ones, N-palmitoyl dopamine-d5 and N-stearoyl
Et3N 3eq, in CH2Cl2 solvent with procedure 3 (Table 1). Al- dopamine-d5, were efficiently synthesized without protective
though several N-acyldopamine syntheses were previously groups in CH2Cl2 under optimized conditions using PPACA as
reported, for example, the mixed anhydride method,1,10,14,15) the condensation agent. The reaction mixture could be directly
EDCI method,12) BOP method,13) and O-(benzotriazol-1- charged on silica-gel column chromatography as the purifica-
yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate (TBTU) tion step in small-scale synthesis. This method was also appli-
method,7) PPACA was used by Walker’s group in 2003 for the cable for synthesizing deuterated N-acyldopamine analogs that
synthesis of N-acyldopamine.4) The advantages of PPACA as can serve as internal standards for quantitative analysis. Thus,
a condensation agent are that 1) PPACA shows a mild reactiv- our simple and efficient synthetic method for N-acyldopamine
ity; therefore, byproducts 3 and 4 were not produced using synthesis may be useful for not only clarifying various func-
this reagent, 2) PPACA is commercially available in solution; tions and mechanisms of action of N-acyldopamines contain-
therefore, slow addition to a reaction flask was possible using ing a specific fatty acid, but also for quantitating endogenous
a syringe in an Argon atmosphere. However, even PPACA N-acyldopamines from biological samples.
produced byproducts 3 and 4 when this reagent was rapidly
added to the reaction mixture.
Experimental
Utilizing the best reaction conditions described above,
Representative Synthetic Procedure: N-Palmitoleoyl
twenty N-acyldopamines, including the two deuterated ana- Dopamine Dopamine hydrochloride (60.7mg, 0.32mmol)
logs N-palmitoyl dopamine-d5 and N-stearoyl dopamine-d5 and palmitoleic acid (91.0µL, 0.32mmol) were mixed in dry
for internal standard use, were synthesized in total (Chart 4). CH2Cl2 (1mL) under an Ar atmosphere, and triethylamine
The yields were moderate, and the starting materials could be (133 µL, 0.96mmol) was added at 0°C. PPACA (50% in ethyl
recovered after silica-gel column chromatography. However, acetate, 200µL, 0.32mmol) was slowly added over 30min at
the use of excess reagents gave over-acylated products 3 and 4 the same temperature, and the reaction mixture was stirred
(entries 15, 16, Table 1). This method was applicable to small- at room temperature overnight. The mixture was worked
scale synthesis of the deuterated analogs16) as well as using up followed by evaporation, and the residue was purified by
rare fatty acids. The reaction mixture in CH2Cl2 could be column chromatography (eluent; EtOAc–hexane=1:1–4:1)
directly charged on silica-gel column chromatography as the to give N-palmitoleoyl dopamine (22.6mg, 18.1%) as a color-

Vol. 64, No. 7 (2016)
Chem. Pharm. Bull.
937
Table 1. Conditions of Condensation Reaction and Products
Entry
Dopamine·HCl
Condensation agent
Amine
Solvent
Procedure
Product (yield (%))
1
2
1eq
1eq
EDCI (1eq)
EDCI (1eq)
DMAP (1eq)
DMAP (1eq)
CH2Cl2
CH2Cl2
1
2
2 (0%)+3 (5.4%)+4 (31.2%)
2 (0%)+3 (minor)+4 (major)
3
4
5
1eq
1eq
1eq
PPACA (1eq)
BOP (1eq)
Et3N (3eq)
Et3N (3eq)
Et3N (3eq)
CH2Cl2
CH2Cl2
CH2Cl2
2
2
2
2 (31.4%) (trace of 3 and 4)
2 (33.4%)+3 (trace)+4 (20.6%)
2 (4.4%)+3 (trace)+4 (8.2%)
EDCI (1eq)
6
7
8
9
1eq
1eq
1eq
1eq
EDCI (1eq)
EDCI (1eq)
EDCI (1eq)
EDCI (1eq)
Et3N (3eq)
Et3N (3eq)
Et3N (3eq)
Et3N (1eq)
CH2Cl2
CH2Cl2
DMF
1
3
1
1
2 (32.8%)+3 (trace)+4 (28.5%)
2 (23.4%)+3 (trace)+4 (18.1%)
2 (20.6%) (trace of 3 and 4)
2 (35.6%) (trace of 3 and 4)
THF
10
11
12
1eq
1eq
1eq
PPACA (1eq)
PPACA (1eq)
PPACA (1eq)
Et3N (1eq+2eq)
Et3N (2eq)
CH2Cl2
CH2Cl2
CH2Cl2
1
1
1
2 (19.3%)
2 (30.4%)
2 (51.8%)
Et3N (3eq)
13
1eq
PPACA (1eq)
Et3N (3eq)
CH2Cl2
3
2 (64.6%)
14
15
16
17
3eq
3eq
3eq
3eq
PPACA (1eq)
PPACA (3eq)
PPACA (1eq)
PPACA (3eq)
Et3N (3eq)
Et3N (3eq)
Et3N (12eq)
Et3N (12eq)
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
1
1
1
1
2 (36.5%)
2 (0%)+3 (minor)+4 (major)
2 (trace)+3 (minor)+4 (major)
2 (21.7%)
1
less oil. H-NMR (400MHz, CDCl3) δ: 0.86 (3H, t, J=6.9Hz), J=7.8Hz), 3.46 (2H, d, J=5.6Hz), 5.36 (1H, brs), 5.45 (1H,
1.25–1.30 (16H, m), 1.56 (2H, m), 1.99 (4H, m), 2.14 (2H, t, brs), 6.36 (1H, brs). HR-MS Calcd for [C24H36D5NO3−H]−
J=7.8Hz), 2.67 (2H, t, J=7.8Hz), 3.46 (2H, q, J=6.7Hz), 5.33 ([M−H]−) 395.3328. Found 395.3327.
(2H, m), 5.70 (1H, t, J=5.6Hz), 6.40 (1H, brs), 6.54 (1H, dd,
J=2.0, 8.0Hz), 6.73 (1H, d, J=2.0Hz), 6.79 (1H, d, J=8.0Hz),
7.91 (1H, brs). 13C-NMR (100MHz, CDCl3) δ: 14.2, 22.7, 25.8,
Physicochemical Data for the Synthetic N-Acyldopamine
N-Tridecanoyl Dopamine14)
A white wax. 1H-NMR (400MHz, CDCl3) δ: 0.86 (3H,
27.3, 27.3, 29.1–29.8 (multiple peaks in the range), 31.9, 35.0, t, J=6.9Hz), 1.23–1.28 (18H, m), 1.57 (2H, m), 2.13 (2H, t,
36.9, 41.1, 115.2, 115.5, 120.5, 129.8, 130.1, 130.4, 143.3, 144.5, J=7.8Hz), 2.69 (2H, t, J=7.1Hz), 3.48 (2H, dt, J=7.1, 5.9Hz),
174.6. High resolution (HR)-MS Calcd for [C24H39NO3+Na]+ 5.55 (1H, brs), 5.74 (1H, brs), 6.57 (1H, dd, J=2.3, 8.2Hz),
([M+Na]+) 412.2822. Found 412.2850.
6.73 (1H, d, J=2.3Hz), 6.79 (1H, d, J=8.2Hz), 7.32 (1H, brs).
N-Palmitoyl Dopamine-d5 According to the same proce- 13C-NMR (100MHz, CDCl3) δ: 14.2, 22.8, 25.8, 29.3–29.7
dure as above using dopamine-d5 hydrochloride (Cambridge (multiple peaks in the range), 32.0, 35.1, 37.0, 40.9, 115.2,
Isotope Lab., Inc., 62.3mg, 0.32mmol) and palmitic acid 115.5, 120.6, 130.9, 143.0, 144.2, 174.6. HR-MS Calcd for
(82.1mg, 0.32mmol), 48.9mg of the product was obtained [C21H35NO3+Na]+ ([M+Na]+) 372.2509. Found 372.2494.
1
(38.5%) as a white wax. H-NMR (400MHz, CDCl3) δ: 0.87
(3H, t, J=6.9Hz), 1.23 (24H, m), 1.58 (2H, m), 2.11 (2H, t,
N-Myristoyl Dopamine14)
A white wax. 1H-NMR (400MHz, CDCl3) δ: 0.87 (3H,

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O-Acetylated analogs di-O-Ac-ODA and di-O-Ac-PALDA were obtained from diacetylation of ODA and PALDA, respectively.
Chart 4. Structures of Endogenous and Potentially Endogenous N-Acyldopamines Synthesized Including Deuterated Compounds with Reaction
Yields
t, J=6.8Hz), 1.23–1.29 (20H, m), 1.57 (2H, m), 2.13 (2H, t, t, J=6.9Hz), 1.23–1.29 (22H, m), 1.58 (2H, m), 2.14 (2H, t,
J=7.6Hz), 2.69 (2H, t, J=7.1Hz), 3.48 (2H, dt, J=6.9, 6.4Hz), J=7.6Hz), 2.69 (2H, t, J=7.1Hz), 3.47 (2H, dt, J=7.1, 6.0Hz),
5.57 (1H, brs), 5.80 (1H, brs), 6.56 (1H, dd, J=2.3, 8.2Hz), 5.57 (1H, brs), 5.84 (1H, brs), 6.56 (1H, dd, J=1.8, 7.8Hz),
6.73 (1H, d, J=2.3Hz), 6.79 (1H, d, J=8.2Hz), 7.40 (1H, brs). 6.73 (1H, d, J=1.8Hz), 6.79 (1H, d, J=7.8Hz), 7.51 (1H, brs).
HR-MS Calcd for [C22H37NO3+Na]+ ([M+Na]+) 386.2666. 13C-NMR (100MHz, CDCl3) δ: 14.2, 22.8, 25.8, 29.3–29.8
Found 386.2679.
(multiple peaks in the range), 32.0, 34.9, 36.9, 40.5, 115.0,
115.2, 120.5, 129.8, 130.6, 143.1, 144.4, 174.1. HR-MS Calcd
N-Pentadecanoyl Dopamine14)
A white wax. 1H-NMR (400MHz, CDCl3) δ: 0.87 (3H, for [C23H39NO3+Na]+ ([M+Na]+) 400.2822. Found 400.2843.

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Chem. Pharm. Bull.
939
N-Palmitoyl Dopamine14)
7.91 (1H, brs). HR-MS Calcd for [C24H39NO3+Na]+ ([M+Na]+)
A white wax. 1H-NMR (400MHz, CDCl3) δ: 0.87 (3H, 412.2822. Found 412.2834.
t, J=6.9Hz), 1.23–1.29 (24H, m), 1.54 (2H, m), 2.11 (2H, t,
J=7.6Hz), 2.69 (2H, t, J=6.9Hz), 3.47 (2H, dt, J=6.9, 6.4Hz),
N-(Z)-Hexadec-11-enoyl Dopamine
A colorless oil. H-NMR (400MHz, CDCl3) δ: 0.88 (3H, t,
1
5.38 (1H, brs), 5.46 (1H, brs), 6.40 (1H, brs), 6.56 (1H, dd, J=6.9Hz), 1.23–1.33 (16H, m), 1.56 (2H, m), 1.97–2.01 (4H,
J=2.3, 8.2Hz), 6.73 (1H, d, J=2.3Hz), 6.79 (1H, d, J=8.2Hz). m), 2.14 (2H, t, J=7.6Hz), 2.68 (2H, t, J=7.1Hz), 3.46 (2H,
HR-MS Calcd for [C24H41NO3+Na]+ ([M+Na]+) 414.2979. dt, J=7.1, 5.9Hz), 5.32–5.35 (2H, m), 5.67 (1H, brs), 6.30
Found 414.2971.
(1H, brs), 6.54 (1H, dd, J=1.8, 7.8Hz), 6.73 (1H, d, J=1.8Hz),
6.79 (1H, d, J=7.8Hz), 7.81 (1H, brs). HR-MS Calcd for
N-Heptadecanoyl Dopamine14)
A white wax. 1H-NMR (400MHz, CDCl3) δ: 0.87 (3H, [C24H39NO3+Na]+ ([M+Na]+) 412.2822. Found 412.2827.
t, J=6.9Hz), 1.23–1.29 (26H, m), 1.55 (2H, m), 2.11 (2H, t,
J=7.6Hz), 2.69 (2H, t, J=6.9Hz), 3.47 (2H, dt, J=6.9, 6.0Hz),
N-Petroselinoyl Dopamine
1
A colorless oil. H-NMR (400MHz, CDCl3) δ: 0.87 (3H, t,
5.40 (1H, brs), 5.46 (1H, brs), 6.46 (1H, brs), 6.58 (1H, dd, J=6.9Hz), 1.24–1.34 (20H, m), 1.58 (2H, m), 1.94–2.01 (4H,
J=1.8, 8.2Hz), 6.73 (1H, d, J=1.8Hz), 6.79 (1H, d, J=8.2Hz). m), 2.15 (2H, t, J=7.6Hz), 2.65 (2H, t, J=7.1Hz), 3.44 (2H, dt,
HR-MS Calcd for [C25H43NO3+Na]+ ([M+Na]+) 428.3135. J=7.1, 5.9Hz), 5.24–5.33 (2H, m), 5.89 (1H, brs), 6.52 (1H, dd,
Found 428.3156.
J=1.8, 7.8Hz), 6.73 (1H, d, J=1.8Hz), 6.79 (1H, d, J=7.8Hz).
N-Stearoyl Dopamine14)
HR-MS Calcd for [C26H43NO3+Na]+ ([M+Na]+) 440.3135.
A white wax. 1H-NMR (400MHz, CDCl3) δ: 0.87 (3H, Found 440.3157.
t, J=6.9Hz), 1.23–1.29 (28H, m), 1.55 (2H, m), 2.11 (2H, t,
J=7.6Hz), 2.69 (2H, t, J=6.9Hz), 3.47 (2H, dt, J=6.9, 6.0Hz),
N-Elaidoyl Dopamine17)
1
A colorless oil. H-NMR (400MHz, CDCl3) δ: 0.87 (3H,
5.35 (1H, brs), 5.45 (1H, brs), 6.32 (1H, brs), 6.58 (1H, dd, t, J=6.9Hz), 1.25–1.30 (20H, m), 1.58 (2H, m), 1.94 (4H, m),
J=1.8, 7.8Hz), 6.73 (1H, d, J=1.8Hz), 6.79 (1H, d, J=7.8Hz). 2.13 (2H, t, J=7.6Hz), 2.69 (2H, t, J=7.1Hz), 3.47 (2H, dt,
HR-MS Calcd for [C26H45NO3+Na]+ ([M+Na]+) 442.3292. J=7.1, 5.9Hz), 5.36 (2H, m), 5.54 (1H, brs), 5.74 (1H, brs),
Found 442.3294.
6.56 (1H, dd, J=1.8, 7.8Hz), 6.73 (1H, d, J=1.8Hz), 6.79 (1H,
N-Nonadecanoyl Dopamine14)
d, J=7.8Hz). HR-MS Calcd for [C26H43NO3+Na]+ ([M+Na]+)
A white wax. 1H-NMR (400MHz, CDCl3) δ: 0.87 (3H, 440.3135. Found 440.3141.
t, J=6.9Hz), 1.23–1.29 (30H, m), 1.55 (2H, m), 2.10 (2H, t,
J=7.6Hz), 2.69 (2H, t, J=6.9Hz), 3.47 (2H, dt, J=6.9, 6.4Hz),
N-cis-Vaccenoyl Dopamine
A colorless oil. H-NMR (400MHz, CDCl3) δ: 0.88 (3H,
1
5.17 (1H, brs), 5.40 (1H, brs), 5.77 (1H, brs), 6.58 (1H, dd, t, J=6.9Hz), 1.23–1.28 (20H, m), 1.56 (2H, m), 1.99 (4H,
J=1.8, 7.8Hz), 6.73 (1H, d, J=1.8Hz), 6.79 (1H, d, J=7.8Hz). m), 2.15 (2H, t, J=7.6Hz), 2.65 (2H, t, J=7.1Hz), 3.44 (2H,
HR-MS Calcd for [C27H47NO3+Na]+ ([M+Na]+) 456.3448. dt, J=7.1, 5.9Hz), 5.33 (2H, m), 5.80 (1H, brs), 6.52 (1H, dd,
Found 456.3468.
J=1.8, 7.8Hz), 6.72 (1H, d, J=1.8Hz), 6.79 (1H, d, J=7.8Hz),
N-Eicosanoyl Dopamine14)
7.91 (1H, brs). HR-MS Calcd for [C26H43NO3+Na]+ ([M+Na]+)
A white wax. 1H-NMR (400MHz, CDCl3) δ: 0.85 (3H, 440.3135. Found 440.3143.
t, J=6.9Hz), 1.22–1.26 (32H, m), 1.52 (2H, m), 2.07 (2H, t,
J=7.8Hz), 2.66 (2H, t, J=6.9Hz), 3.43 (2H, t, J=6.9Hz), 5.41
N-Linoleoyl Dopamine7)
1
A colorless oil. H-NMR (400MHz, CDCl3) δ: 0.87 (3H,
(1H, brs), 5.88 (1H, brs), 6.52 (1H, dd, J=1.8, 7.8Hz), 6.67 t, J=6.9Hz), 1.24–1.36 (14H, m), 1.56 (2H, m), 1.99–2.06
(1H, d, J=1.8Hz), 6.74 (1H, d, J=7.8Hz). HR-MS Calcd for (4H, m), 2.14 (2H, t, J=7.6Hz), 2.64 (2H, t, J=7.1Hz), 2.75
[C28H49NO3+Na]+ ([M+Na]+) 470.3605. Found 470.3603.
(2H, t, J=6.4Hz), 3.43 (2H, dt, J=7.1, 5.9Hz), 5.28–5.38 (4H,
m), 5.88 (1H, t, J=5.7Hz), 6.52 (1H, dd, J=1.8, 8.2Hz), 6.73
N-Myristoleoyl Dopamine
1
A colorless oil. H-NMR (400MHz, CDCl3) δ: 0.87 (3H, t, (1H, d, J=1.8Hz), 6.79 (1H, d, J=8.2Hz), 7.00 (1H, brs), 7.87
J=6.9Hz), 1.25–1.32 (12H, m), 1.57 (2H, m), 1.96–2.03 (4H, (1H, brs). 13C-NMR (100MHz, CDCl3) δ: 14.2, 22.7, 25.7,
m), 2.14 (2H, t, J=7.6Hz), 2.68 (2H, t, J=7.1Hz), 3.47 (2H, 25.9, 27.3, 29.2–29.8 (multiple peaks in the range), 31.6, 34.9,
dt, J=7.1, 5.9Hz), 5.31–5.34 (2H, m), 5.63 (1H, brs), 6.09 36.9, 41.2, 120.5, 128.0, 128.2, 130.1, 130.3, 130.5, 143.3,
(1H, brs), 6.55 (1H, dd, J=1.8, 7.8Hz), 6.73 (1H, d, J=1.8Hz), 144.6, 174.8. HR-MS Calcd for [C26H41NO3+Na]+ ([M+Na]+)
6.79 (1H, d, J=7.8Hz), 7.77 (1H, brs). HR-MS Calcd for 438.2979. Found 438.3003.
[C22H35NO3+Na]+ ([M+Na]+) 384.2509. Found 384.2520.
N-Eicosapentaenoyl Dopamine2)
A colorless oil. H-NMR (400MHz, CDCl3) δ: 0.96 (3H, t,
1
N-Sapienoyl Dopamine
1
A colorless oil. H-NMR (400MHz, CDCl3) δ: 0.86 (3H, t, J=7.3Hz), 1.67 (2H, m), 2.06 (4H, m), 2.15 (2H, t, J=7.6Hz),
J=6.9Hz), 1.24–1.33 (16H, m), 1.58 (2H, m), 1.94–2.02 (4H, 2.67 (2H, t, J=7.1Hz), 2.75–2.82 (8H, m), 3.46 (2H, dt, J=7.1,
m), 2.16 (2H, t, J=7.6Hz), 2.66 (2H, t, J=7.1Hz), 3.45 (2H, dt, 5.9Hz), 5.28–5.40 (10H, m), 5.66 (1H, brs), 6.27 (1H, brs), 6.54
J=7.1, 5.9Hz), 5.25–5.37 (2H, m), 5.89 (1H, brs), 6.52 (1H, dd, (1H, dd, J=1.8, 8.2Hz), 6.73 (1H, d, J=1.8Hz), 6.79 (1H, d,
J=1.8, 7.8Hz), 6.74 (1H, d, J=1.8Hz), 6.79 (1H, d, J=7.8Hz). J=8.2Hz), 7.75 (1H, brs). HR-MS Calcd for [C28H39NO3+Na]+
HR-MS Calcd for [C24H39NO3+Na]+ ([M+Na]+) 412.2822. ([M+Na]+) 460.2822. Found 460.2827.
Found 412.2839.
N-(E)-Hexadec-9-enoyl Dopamine
N-Stearoyl Dopamine-d5
A white wax. H-NMR (400MHz, CDCl3) δ: 0.87 (3H, t,
1
1
A colorless oil. H-NMR (400MHz, CDCl3) δ: 0.86 (3H, t, J=6.9Hz), 1.21–1.27 (28H, m), 1.56 (2H, m), 2.15 (2H, m), 3.50
J=6.9Hz), 1.24–1.31 (16H, m), 1.56 (2H, m), 1.91–1.97 (4H, (2H, m), 6.30 (1H, brs). HR-MS Calcd for [C26H39D5NO3−H]−
m), 2.14 (2H, t, J=7.6Hz), 2.66 (2H, t, J=7.1Hz), 3.48 (2H, ([M−H]−) 423.3641. Found 423.3628.
dt, J=7.1, 5.9Hz), 5.36 (2H, m), 5.74 (1H, brs), 6.53 (1H, dd,
J=1.8, 7.8Hz), 6.73 (1H, d, J=1.8Hz), 6.79 (1H, d, J=7.8Hz),
Di-O-Ac-ODA
1
A white wax. H-NMR (400MHz, CDCl3) δ: 0.86 (3H, t,

940
Chem. Pharm. Bull.
Vol. 64, No. 7 (2016)
Proc. Natl. Acad. Sci. U.S.A., 99, 8400–8405 (2002).
J=6.9Hz), 1.23–1.29 (20H, m), 1.57 (2H, m), 1.99 (4H, m),
2.10 (2H, t, J=7.6Hz), 2.26 (6H, s), 2.78 (2H, t, J=6.6Hz),
3.47 (2H, dt, J=6.6, 5.2Hz), 5.32 (2H, m), 5.55 (1H, brs),
6.99 (1H, d, J=1.8Hz), 7.04 (1H, dd, J=1.8, 8.2Hz), 7.10 (1H,
d, J=8.2Hz). HR-MS Calcd for [C30H47NO5+K]+ ([M+K]+)
540.3086. Found 540.3085.
4) Chu C. J., Huang S. M., De Petrocellis L., Bisogno T., Ewing S. A.,
Miller J. D., Zipkin R. E., Daddario N., Appendino G., Di Marzo V.,
Walker J. M., J. Biol. Chem., 278, 13633–13639 (2003).
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M., Di Marzo V., Br. J. Pharmacol., 143, 251–256 (2004).
6) Yoo J. M., Park E. S., Kim M. R., Sok D.-E., Lipids, 48, 383–393
(2013).
Di-O-Ac-PALDA
A white wax. 1H-NMR (400MHz, CDCl3) δ: 0.86 (3H,
t, J=6.9Hz), 1.23–1.27 (24H, m), 1.57 (2H, m), 2.12 (2H, t,
J=7.6Hz), 2.26 (6H, s), 2.78 (2H, t, J=6.6Hz), 3.47 (2H, dt,
J=6.6, 6.0Hz), 5.66 (1H, brs), 6.99 (1H, d, J=1.4Hz), 7.04
(1H, dd, J=1.4, 8.2Hz), 7.10 (1H, d, J=8.2Hz). HR-MS Calcd
for [C28H45NO5+Na]+ ([M+Na]+) 498.3190. Found 498.3207.
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(2008).
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Acknowledgments We thank Mr. Elliot Bradshaw
(RIKEN) for proofreading. This work was supported in part
by Grants-in-Aid from the Japan Society for the Promotion
of Science (No. 24790004 to Y.M. and No. 24590021 to A.K.)
and AMED-CREST, AMED.
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Lett., 17, 4575–4578 (2007).
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Proced. Int., 30, 699–702 (1998).
Conflict of Interest The authors declare no conflict of
interest.
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Chem. B, 117, 8747–8757 (2013).
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e9713 (2010).
16) In Chart 4, N-palmitoyl dopamine was obtained in 52.2% yield with
204.4mg using a synthetic scale, and the deuterated counterpart was
obtained in 38.5% yield with 82.1mg scale (Experimental), this dif-
ference of yield might be due to the synthetic scale.
17) Gaddis B. D., Rubert Pérez C. M., Chmielewski J., Bioorg. Med.
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References and Notes
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